In a mixing bowl, combine the ricotta cheese, Italian seasoning, garlic powder, onion powder, and a pinch of salt and pepper. Mix well until smooth.
Spray the inside of the crockpot with cooking spray to prevent sticking.
Spread a thin layer of marinara sauce at the bottom of the crockpot to create a base.
Layer half of the refrigerated ravioli over the sauce, spreading them out as evenly as possible.
Spoon half of the ricotta mixture over the ravioli, followed by a layer of 1 cup of mozzarella cheese and a sprinkle of 1/2 cup of Parmesan cheese.
Add another layer of marinara sauce over the cheese mixture, followed by the remaining ravioli.
Repeat the process with the remaining ricotta mixture, the rest of the marinara sauce, and finish with the remaining mozzarella and Parmesan cheese on top.
Cover the crockpot and cook on low for 4-5 hours or on high for 2-3 hours, until the cheese is melted and bubbly.
Once cooked, turn off the crockpot and let it sit for about 10 minutes before serving.
Garnish with fresh basil leaves before serving if desired.