In a large skillet, heat oil over medium heat. Add beef and cook over medium heat, stirring and breaking up with a spoon, until browned.
Remove from skillet with slotted spoon.
Add mushrooms to skillet; cook over medium-high heat until browned.
Return beef to skillet, stir in sour cream, peas, salt and pepper. Bring to a simmer.
Serve over noodles.