Bring a pot of salted water to a boil. Cook egg noodles according to package directions until just tender. Drain and set aside.
While noodles cook, heat a large skillet over medium heat. Add ground beef and cook for 6-8 minutes, breaking it apart with a wooden spoon, until fully browned with no pink remaining. Drain excess fat, leaving about 1 tablespoon. Transfer beef to a plate.
In the same skillet, melt butter over medium heat. Add flour and whisk constantly for 2 minutes until the mixture smells toasted and turns golden.
Gradually pour in chicken broth while whisking continuously. Continue whisking for 3-4 minutes until the sauce thickens and becomes smooth.
Slowly add milk while stirring constantly. Cook over medium heat for 5-7 minutes, stirring frequently, until the sauce thickens to a creamy consistency.
Stir in garlic powder, onion powder, salt, and black pepper until well combined.
Reduce heat to low. Add the cooked egg noodles and browned ground beef to the skillet. Stir gently until everything is well combined and heated through.
Remove skillet from heat completely. Gently fold in sour cream until fully incorporated and the sauce is smooth and creamy.
Serve immediately while hot. Garnish with fresh parsley if desired.
