In a large skillet, heat a tablespoon of olive oil over medium heat.
Add chopped onions and cook for about 3-4 minutes, or until translucent. Add garlic and stir for 30 seconds.
Reduce heat to avoid splatters, and stir in spaghetti sauce, water and seasonings. Bring heat up to medium and let sauce heat through.
Stir in frozen ravioli.
Bring to a boil, reduce the heat to low and cover for 20 minutes. Remove from heat.
Sprinkle in half the Mozzarella cheese and stir it into the sauce until it melts.
Sprinkle remaining cheese and parsley on top and replace cover to let all the cheese melt, about 5 minutes.