In a medium bowl, whisk sour cream, eggs, dill and cheese; add mushrooms and salt and pepper to taste.
Mix and set aside.
Bring a large pot of lightly salted water to a boil.
Add pasta and cook for 8 to 10 minutes or until al dente; drain and return to pot.
Over medium heat, pour sour cream mixture into pot with pasta until sauce begins to boil; stir frequently. Be careful to not overcook this sauce or it will become sticky.
Add the cream mixture to pasta and cook over medium heat; stir frequently for about 3 minutes or until sauce begins to bubble. Be careful not to overcook the sauce.