Bring a large pot of water to a boil and cook the pasta according to the package directions. Drain, rinse with cold water, and set aside.
Add ground beef to a large skillet over medium-high heat. Cook until the meat is browned, breaking it apart into small pieces. Add the onion and garlic, and sauté until translucent and soft. Drain off excess grease.
Lower heat to medium, then add the mushrooms and cook for 5-7 minutes, until they are soft.
In a bowl, whisk together black pepper, Italian seasoning, paprika, salt, beef broth, cornstarch, Dijon mustard, and heavy cream. Pour into the skillet and bring to a light boil, reduce heat to low and simmer for 5 minutes stirring occasionally.
Stir in sour cream until well incorporated.
Add noodles and mix until fully coated, and enjoy!