There’s something about the smell of Italian sausage sizzling with peppers and onions that instantly makes a house feel like home. This Italian Sausage & Pepper Casserole captures those classic street fair flavors in a simple one-pan dinner that’s ready in under an hour. Savory sausage mingles with sweet bell peppers in a rich tomato sauce, then everything gets topped with melted mozzarella that turns golden and bubbly in the oven.
I make this when I need a satisfying dinner without spending my evening in the kitchen. It’s forgiving enough for weeknights but impressive enough to serve to guests. The beauty is in its simplicity—just brown the sausage, sauté the vegetables, add the sauce, top with cheese, and bake. The oven does most of the work while you set the table or help with homework.
Why You’ll Love This Italian Sausage & Pepper Casserole
This recipe delivers big, bold flavor with minimal hands-on time. Once you’ve browned the sausage and softened the vegetables, the oven takes over, leaving you free to tackle other things. The combination of sweet bell peppers and savory sausage is naturally balanced, and the tomato sauce ties everything together with herbs and richness.
It works beautifully as a low-carb dinner on its own, or you can serve it over pasta or with bread to make it stretch further for larger families. The protein from the sausage keeps everyone satisfied, and the vegetables add color and nutrition without feeling like an afterthought. Leftovers taste even better the next day once the flavors have had time to develop.
This dish is budget-friendly and uses ingredients you probably already have or can easily find at any grocery store. It’s also incredibly flexible—swap the sausage variety, change up the peppers, add mushrooms or zucchini. The basic formula is solid enough that you can adapt it based on what’s in your refrigerator or what your family prefers.
Ingredients for Italian Sausage & Pepper Casserole
I always buy good-quality Italian sausage for this recipe because it’s the foundation of the dish. Choose sweet if you want mellow, fennel-forward flavor, or spicy if you like a little heat. Look for sausage with visible seasoning and fat marbling—that fat renders during cooking and adds tremendous flavor to the vegetables and sauce.
- 1 lb Italian sausage (sweet or spicy)
- 2 bell peppers (one red, one green), sliced
- 1 onion, chopped
- 3 cloves garlic, minced
- 1 can (14.5 oz) diced tomatoes
- 1 can (8 oz) tomato sauce
- 1 tsp Italian seasoning
- 1 cup shredded mozzarella cheese
- Salt and pepper, to taste
The bell peppers bring sweetness and color to the dish. I use one red and one green for visual appeal and because they offer slightly different flavor profiles—red is sweeter, green is slightly more bitter and grassy. You can use all red or even throw in a yellow or orange pepper if that’s what you have. Slice them into strips about ¼-inch thick so they soften nicely during cooking without turning mushy.
Fresh garlic makes a noticeable difference compared to jarred or powdered versions. Three cloves gives you enough garlicky punch without overwhelming the other flavors. For the cheese, shred mozzarella from a block if possible. Pre-shredded works in a pinch, but block cheese melts more smoothly and doesn’t have the anti-caking agents that can affect texture. I prefer whole milk mozzarella for maximum flavor and melt quality.
The diced tomatoes add chunks and texture while the tomato sauce creates a cohesive base. Look for canned tomatoes without added seasonings so you can control the flavor yourself. Italian seasoning typically contains basil, oregano, thyme, and rosemary—it’s the shortcut that gives this dish its Italian character without measuring multiple dried herbs.
How to Make Italian Sausage & Pepper Casserole
This recipe comes together in two main phases: stovetop cooking to develop flavor, then oven baking to meld everything together and brown the cheese. I find that taking an extra minute to really brown the sausage and caramelize the vegetables makes all the difference in the final dish.
Brown the Sausage Preheat your oven to 375°F while you work on the stovetop portion. Heat a large skillet over medium heat—no oil needed since the sausage has plenty of fat. Remove the sausage from its casing if necessary and add it to the hot skillet. Break it apart with a wooden spoon or spatula as it cooks, creating bite-sized crumbles. Cook for about 8-10 minutes until it’s well browned with crispy edges in spots. Don’t rush this step—good browning equals good flavor. Use a slotted spoon to transfer the cooked sausage to a plate, leaving about 2 tablespoons of fat in the pan.
Cook the Vegetables Add your sliced peppers and chopped onion to the same skillet with the reserved sausage fat. The fat carries all that savory flavor from the meat and helps the vegetables caramelize beautifully. Cook for about 5 minutes, stirring occasionally, until the peppers start to soften and the onions turn translucent. Add the minced garlic and cook for another minute until fragrant. Watch carefully during this last minute because garlic can burn quickly, turning bitter.
Build the Sauce Return the browned sausage to the skillet with the vegetables. Pour in the diced tomatoes with their juice and the tomato sauce. Sprinkle in the Italian seasoning, then season with salt and pepper—go light on the salt at first since the sausage is already seasoned. Stir everything together and let it simmer for 3-4 minutes. This brief simmer gives the flavors time to get acquainted and lets some of the liquid reduce slightly, concentrating the taste.
Assemble and Bake Transfer the entire mixture to a 9×13-inch casserole dish, spreading it into an even layer. Sprinkle the shredded mozzarella evenly over the top. Slide the dish into your preheated oven and bake for 25-30 minutes. You’re looking for the cheese to melt completely, turn golden brown in spots, and for the sauce to bubble vigorously around the edges. The bubbling tells you everything is heated through and the flavors have married. Let it rest for 5 minutes before serving—this allows the sauce to thicken just enough that it doesn’t run all over the plate when you scoop it.
What to Serve with Italian Sausage & Pepper Casserole
This casserole is rich and satisfying, so I like pairing it with lighter sides that add freshness or help soak up the delicious sauce. The beauty of this dish is its versatility—it works equally well as a standalone low-carb meal or as part of a more substantial spread.
Garlic Bread: Crusty Italian bread brushed with butter, garlic, and herbs, then toasted until golden is the classic choice. It’s perfect for mopping up every drop of that tomato sauce. Make it cheesy by adding mozzarella or parmesan before toasting. The crispy, buttery bread provides textural contrast to the tender casserole.
Simple Green Salad: Mixed greens with cherry tomatoes, cucumber, and red onion dressed in a bright Italian vinaigrette balances the richness beautifully. The acidity and crispness of the salad refreshes your palate between bites. A squeeze of lemon juice in the dressing adds extra brightness that cuts through the cheese and sausage.
Pasta: Serve the casserole over cooked penne, rigatoni, or spaghetti to turn it into a more filling meal that stretches to feed extra people. The pasta soaks up the sauce and adds substance. This transforms it into a complete one-dish dinner that needs nothing else.
Roasted Vegetables: Zucchini, eggplant, or cherry tomatoes tossed with olive oil and roasted at 425°F for about 20 minutes add more vegetables to the meal without feeling redundant. The caramelization from roasting brings out natural sweetness that complements the savory casserole. Sprinkle with fresh basil before serving.
Caesar Salad: Crisp romaine lettuce with creamy Caesar dressing, parmesan shavings, and crunchy croutons is a restaurant-quality side that feels special. The rich dressing and crunchy elements play well against the soft, saucy casserole. Make or buy good quality dressing—it makes a real difference.
Polenta: Creamy, buttery polenta serves as a wonderful bed for the casserole, much like pasta but with a different texture and corn flavor. The smooth polenta provides a neutral canvas that lets the bold Italian flavors shine. Instant polenta takes just 5 minutes to make.
Pro Tips & Variations
Remove Sausage Casings Carefully: If your sausage comes in links rather than loose, use a sharp knife to slit the casing lengthwise, then peel it away. The casing is tough and chewy, so removing it improves the texture significantly. Some grocery stores sell loose Italian sausage, which eliminates this step entirely.
Don’t Crowd the Pan: If your skillet isn’t large enough to brown the sausage in a single layer, work in batches. Crowding causes the meat to steam rather than brown, and you’ll miss out on those flavorful crispy bits. A 12-inch skillet is ideal for this recipe.
Boost the Vegetables: Add sliced mushrooms, diced zucchini, or quartered artichoke hearts to increase the vegetable content. Sauté them along with the peppers and onions. These additions bulk up the dish without adding much cost and make it feel even heartier.
Try Different Cheeses: Provolone adds a sharper, more complex flavor than mozzarella. A blend of mozzarella and parmesan gives you stretchiness plus that nutty, salty parmesan kick. Fontina melts beautifully and has a subtle earthiness that works wonderfully with sausage.
Make It Lighter: Swap regular Italian sausage for turkey or chicken Italian sausage to reduce calories and fat while keeping the seasoning. You might need to add a tablespoon of olive oil to the pan since these leaner sausages don’t release as much fat. The flavor is still excellent, just slightly lighter.
Add Heat: If you love spicy food, use hot Italian sausage and add ½ teaspoon of red pepper flakes when you add the tomatoes. Fresh jalapeño or banana peppers mixed in with the bell peppers bring a different kind of heat that’s bright and fresh rather than just burning.
Make It Ahead: Prepare the entire casserole through step 5, then cover and refrigerate for up to 24 hours before baking. Add 10 minutes to the baking time since you’re starting with a cold dish. This strategy is perfect for entertaining or meal prep.
Storage & Reheating Tips
Store leftovers in an airtight container in the refrigerator for up to 4 days. The casserole reheats beautifully, often tasting even better the next day once the flavors have melded. I reheat individual portions in the microwave for 2-3 minutes on medium power, stirring halfway through. For larger portions, cover with foil and reheat in a 350°F oven for 15-20 minutes until warmed through.
This casserole freezes well for up to 3 months. Let it cool completely after baking, then portion it into freezer-safe containers or wrap the entire dish tightly in plastic wrap and foil. Thaw overnight in the refrigerator before reheating. The texture of the peppers softens slightly after freezing, but the flavor remains excellent.
For meal prep, you can portion the cooked casserole into individual containers for grab-and-go lunches throughout the week. It pairs well with a side salad or some fresh fruit. The high protein content from the sausage makes it a satisfying midday meal that keeps you full until dinner.
Common Questions
Can I use a different type of sausage? Absolutely. Ground beef or turkey with added Italian seasoning works well if you can’t find Italian sausage. Andouille or chorizo creates a completely different but equally delicious flavor profile. Even breakfast sausage in a pinch will work, though the flavor will be milder. Adjust your seasonings based on what the sausage brings to the dish.
What if I don’t have Italian seasoning? Mix together ½ teaspoon each of dried basil and dried oregano, plus a pinch of thyme and garlic powder. This combination captures the essence of Italian seasoning. Fresh herbs work too—use about three times as much fresh basil and oregano, adding them at the end of cooking for maximum flavor.
How do I know when the peppers are done? They should be tender enough to pierce easily with a fork but still hold their shape. If you prefer softer vegetables, add an extra 5 minutes to the initial sauté time. Some people like a bit of crunch remaining in their peppers, while others prefer them very soft—adjust to your preference.
Can I make this in a slow cooker? Yes, brown the sausage and sauté the vegetables on the stovetop first as directed, then transfer everything to a slow cooker. Cook on low for 4-5 hours or high for 2-3 hours. Add the cheese during the last 15 minutes with the lid on so it melts properly. The slow cooker method intensifies the flavors even more.
How do I prevent the cheese from burning? If the cheese starts browning too quickly but the casserole isn’t bubbling yet, tent the dish loosely with aluminum foil for the remaining baking time. The foil prevents over-browning while allowing the dish to continue cooking through. You can remove it for the last 5 minutes if you want more color on top.
This casserole has earned a permanent spot in my dinner rotation because it delivers restaurant-quality Italian flavors with minimal fuss. The combination of savory sausage, sweet peppers, tangy tomato sauce, and melted cheese is timeless and universally loved. Whether you serve it as a low-carb main or pile it over pasta, it’s the kind of dinner that makes everyone happy without keeping you stuck in the kitchen all evening.
Italian Sausage & Pepper Casserole
Ingredients
Equipment
Method
- Preheat your oven to 375°F (190°C).
- In a large skillet over medium heat, cook the Italian sausage until browned, breaking it into bite-sized pieces as it cooks, about 8-10 minutes. Transfer to a plate using a slotted spoon, leaving about 2 tablespoons of fat in the pan.
- Add the sliced bell peppers and chopped onion to the skillet with the reserved fat. Sauté for about 5 minutes until vegetables start to soften. Add minced garlic and cook for 1 minute more until fragrant.
- Return the browned sausage to the skillet. Stir in the diced tomatoes with their juice, tomato sauce, Italian seasoning, salt, and pepper. Let the mixture simmer for 3-4 minutes to allow flavors to meld.
- Transfer the sausage and vegetable mixture to a 9×13-inch casserole dish, spreading it into an even layer. Sprinkle the shredded mozzarella cheese evenly over the top.
- Bake for 25-30 minutes until the cheese is melted, golden brown in spots, and the sauce is bubbling around the edges. Let rest for 5 minutes before serving.
