Heat a tablespoon of olive oil in a saucepan, saute 1 clove of minced garlic and 1/2 finely chopped onion until the onion is tender. Add 1 can/jar of your favorite prepared pasta sauce and a 15 ounce can of tomato sauce. Season with Oregano, Basil and parsley.
Spray your slowcooker with nonstick spray, place 1 cup of sauce mixture in the bottom, add 1 package (25 oz) of frozen cheese ravioli. Top with 1 cup of shredded mozzarella cheese and dollops of ricotta cheese. Top with more sauce and layer another package of ravioli, cheese and the rest of the sauce.
Cover and cook on low for 4-5 hours.