"Chicago Style" Pizza
["1 1/2 lb. ground beef", "1/2 c. chopped onion", "2 Tbsp. grated Parmesan cheese", "1 to 1 1/2 tsp. oregano", "1 1/4 tsp. salt", "1/2 tsp. pepper", "1 small can tomato paste", "1 (10 biscuit) can refrigerator buttermilk or country-style biscuits", "1 (No. 202) can (1/4 c.) mushroom stems and pieces, drained", "1 tomato, sliced", "1 c. (4 oz.) shredded Mozzarella cheese"]
["Heat oven to 350\u00b0.", "Grease 9-inch pie pan.", "Brown ground beef and onions; drain.", "Stir in tomato paste, 1 tablespoon Parmesan cheese, oregano, salt and pepper.", "Simmer while preparing crust."]
["ground beef", "onion", "Parmesan cheese", "oregano", "salt", "pepper", "tomato paste", "refrigerator buttermilk", "mushroom stems", "tomato", "Mozzarella cheese"]