Tuxedo Mushroom Burgers

In skillet sauté mushrooms in butter with the garlic, 1 teaspoon of the oregano, and the salt and pepper until just tender. Remove from heat; stir in Parmesan cheese. Keep warm.

Season beef with remaining teaspoon oregano and salt and pepper. Form into 4 or 6 equal balls. Make a large depression in each; fill cavities with half of the sautéed mushrooms, dividing equally. Bring beef up around mushrooms to enclose; press gently to form patties. Broil or grill to desired doneness. Top with remaining sautéed mushrooms. Serve with sour cream or mustard, as desired.