Slow Cooker Cheesy Ravioli Casserole I made this tonight, but with a few changes: I only used an 8 oz can of tomato sauce & I added 3/4 c. red wine. I simmered all the sauces, liquid, onions & garlic for about 5-10 min. I did layers of sauce, pasta, cheeses (incl. parmesan) & repeated twice. Final layer was sauce & parmesan cheese. I cooked it on high for 2 1/2-3 1/2 hours & had no problem with the pasta sticking together as others have had. I used frozen cheese ravioli from Cash N Carry. Hope that helps. I liked this recipe b/c usually when I boil my ravioli it falls apart & filling falls out.