Slow-Cooker Cheesy Ravioli Casserole (Crowd Size)

INGREDIENTS

packages (25 ounces each) frozen beef-filled ravioli, frozen

large clove Garlic

Onion, chopped (1/2 cup), medium

1/4 cup

Parsley, fresh

1 can

Four cheese-flavored spaghetti sauce

1 can

Tomato sauce

1 tsp

Italian seasoning

1 tbsp

Olive or vegetable oil

2 cups

Mozzarella cheese