In a skillet, brown the ground beef or turkey over medium heat, seasoning with salt and pepper.
In a bowl, mix ricotta cheese, egg, Italian seasoning, and a pinch of salt.
Spread a thin layer of marinara sauce at the bottom of the crockpot.
Place 3 lasagna noodles over the sauce, breaking them if necessary.
Layer half of the ricotta mixture over the noodles.
Add half of the ground meat on top of the ricotta.
Sprinkle with mozzarella cheese and a bit of Parmesan.
Repeat the layering process: sauce, noodles, ricotta, meat, and cheeses.
Finish with a layer of noodles, followed by the remaining marinara sauce and mozzarella.
Cover and cook on low for 4 hours or high for 2 hours until bubbly.