1. Brown the ground beef or sausage in a skillet over medium heat, breaking it apart as it cooks. Add the diced onion and minced garlic; cook until softened.
2. Drain excess fat. Stir in marinara sauce, tomato sauce, basil, oregano, salt, and pepper. Let it simmer for a few minutes.
3. In a medium bowl, mix ricotta cheese, egg, half of the mozzarella, and half of the Parmesan until combined.
4. Spread a thin layer of meat sauce on the bottom of the slow cooker. Break lasagna noodles to fit and arrange a single layer over the sauce.
5. Spread a layer of the ricotta mixture over the noodles, then add more meat sauce. Repeat the layers until all ingredients are used, finishing with sauce and the remaining mozzarella and Parmesan on top.
6. Cover and cook on low for 4–6 hours or until the noodles are tender. Turn off the heat and let it rest for about 15 minutes before serving. Garnish with fresh parsley or basil if desired.

Slow Cooker Tips

1. Use broken lasagna noodles or wide pasta to keep the right texture. Whole noodles take too long and can get mushy. Adding cheese at the end keeps it creamy and fresh.
2. Don’t overcook the soup. The noodles should be tender but not falling apart. If it looks too thick, add a little extra broth to adjust consistency.