Bring a large pot of salted water to a boil. Cook egg noodles according to package directions until tender but still slightly firm. Drain and set aside.

While noodles cook, heat a large skillet over medium heat. Add ground beef and cook, breaking it up with a spoon, for 6-8 minutes until no pink remains and beef is browned. Drain excess fat and transfer beef to a plate.

In the same skillet over medium heat, melt the butter. Add flour and whisk continuously for about 2 minutes until the mixture turns light golden and smells slightly nutty.

Gradually pour in beef broth while whisking constantly. Continue whisking for 3-4 minutes until sauce thickens and becomes smooth.

Slowly whisk in the milk, continuing to stir over medium heat for 5-7 minutes until the sauce thickens to a creamy consistency that coats the back of a spoon.

Stir in garlic powder, onion powder, black pepper, and salt until evenly distributed throughout the sauce.

Reduce heat to low. Add cooked egg noodles and browned ground beef to the skillet. Toss everything together until well combined and heated through.

Remove from heat completely. Gently fold in sour cream, stirring until fully incorporated and sauce is smooth and glossy. Serve hot.