- Lightly spray or grease the bottom of the slow cooker.
- Spread half of the marinara sauce evenly on the bottom.
- Arrange half of the frozen ravioli in a single layer over the sauce.
- Spoon half of the beef-onion mixture over the ravioli.
- Sprinkle 1 cup of shredded mozzarella cheese over the meat.
- Repeat the layering: remaining marinara sauce, remaining ravioli, remaining beef mixture, and top with the final cup of cheese.
Optional: Sprinkle grated Parmesan on the top layer for added sharpness.
Step 3: Cook Low and Slow
Cover the crockpot with its lid. Set to LOW heat and cook for 3 to 4 hours. Check at the 3-hour mark: the ravioli should be tender, and cheese fully melted.
Do not overcook! If left too long, ravioli may become mushy.
Step 4: Rest and Serve
Once cooked, turn off the heat and let the lasagna rest for 10 minutes before serving. This helps the layers set and makes it easier to spoon out portions. Garnish with chopped parsley or fresh basil if desired.
Pair with garlic bread, salad, or roasted veggies for a complete meal.
This recipe serves 6 hearty portions, with each serving size being about 1 ½ cups. The estimated calories per serving are ~450–500 kcal based on regular ground beef and full-fat cheese.
