In a bowl, mix the ricotta cheese, Italian seasoning, garlic powder, salt, and pepper until well combined. Set aside.
Spread 1 cup of marinara sauce on the bottom of the crockpot.
Layer half of the frozen ravioli over the sauce, followed by half of the cooked ground beef or sausage.
Spoon half of the ricotta mixture over the meat, then sprinkle with 1 cup of mozzarella cheese.
Repeat the layers: add another cup of marinara sauce, the remaining ravioli, the remaining meat, the rest of the ricotta mixture, and top with the remaining marinara sauce.
Finish with the remaining mozzarella cheese and sprinkle the Parmesan cheese on top.
Cover and cook on low for 4 to 6 hours or until the ravioli is tender and the cheese is melted and bubbly.
Once cooked, let it sit for 10 minutes before serving. Garnish with fresh basil leaves if desired.