Without a doubt, this is one of my top treats for the season! My husband always requests it

1 pound beef sirloin, thinly sliced
12 ounces egg noodles
2 tablespoons olive oil
1 onion, finely chopped
3 cloves garlic, minced
8 ounces mushrooms, sliced
1 cup beef broth
1 cup heavy cream
1/2 cup sour cream
1 cup grated Parmesan cheese
1/2 cup grated mozzarella cheese
1/4 cup all-purpose flour
2 tablespoons butter
Salt and pepper to taste
2 tablespoons fresh parsley, chopped