Preheat oven to 350°F (175°C). Cook egg noodles according to package directions. Drain and set aside.
In a large skillet, brown ground beef over medium heat. Drain off any excess grease. Add onion and mushrooms and cook until softened, about 5 minutes. Stir in garlic and cook for another minute.
Stir in flour until well combined. Gradually whisk in beef broth, then bring to a simmer. Cook until sauce has thickened slightly, about 3-5 minutes.
Remove from heat and stir in sour cream, Dijon mustard, and paprika. Season with salt and pepper to taste.
Combine cooked egg noodles and ground beef mixture in a greased 9x13 inch baking dish. Stir well to combine.
Bake in preheated oven for 20-25 minutes, or until heated through and bubbly.