Prepare the Meat Sauce

In a skillet over medium heat, cook the ground beef or sausage with the diced onion until browned, breaking it up as it cooks. Add the minced garlic and cook for another minute. Drain excess grease if necessary. Stir in the marinara sauce, tomato sauce, Italian seasoning, salt, and pepper. Let the sauce simmer for a few minutes, then remove from heat.

Make the Cheese Mixture

In a mixing bowl, combine the ricotta cheese, 1 cup of shredded mozzarella, grated Parmesan, and the egg. Mix until smooth and set aside.

Layer the Ingredients in the Crockpot

Spray the crockpot with cooking spray to prevent sticking. Spread a thin layer of meat sauce on the bottom. Break lasagna noodles to fit in an even layer over the sauce. Spread a portion of the ricotta mixture over the noodles, followed by more meat sauce. Repeat the layers (noodles, ricotta mixture, sauce) until all ingredients are used, ending with a layer of meat sauce on top.

Top with Cheese

Sprinkle an additional ½ cup of mozzarella cheese on top of the final layer of sauce.

Cook the Lasagna

Cover and cook on low for 4-5 hours, or until the noodles are tender and the cheese is melted. Avoid overcooking to prevent dry edges.

Serve

Garnish with fresh basil or parsley if desired. Use a spatula to scoop and serve warm.