Chicken Pizzarella
["1 Tbsp. olive oil", "2 Tbsp. onion, finely chopped", "1 c. mushrooms, thickly sliced", "1 small clove garlic, minced", "1/2 tsp. oregano", "1 (8 oz.) can tomato sauce", "pepper to taste", "8 chicken breast halves, boneless and skins removed", "1 c. sliced Mozzarella cheese"]
["Heat oven to 350\u00b0.", "In a small saucepan, heat oil.", "Add onion, mushrooms, garlic and oregano.", "Cook over low heat, stirring occasionally, until onion is soft.", "Stir in tomato sauce and pepper.", "Place chicken in 2-quart baking dish; cover with sauce. Bake, uncovered, 35 minutes.", "Put Mozzarella on top and continue baking 5 more minutes or until cheese is bubbling."]
["olive oil", "onion", "mushrooms", "clove garlic", "oregano", "tomato sauce", "pepper", "chicken", "Mozzarella cheese"]