Cook ground beef, onion, and garlic in a large saucepan until no pink remains. Drain fat.
Stir in marinara sauce, diced tomatoes with juices, and italian seasoning. Simmer 5-7 minutes or until thickened. Season with salt & pepper to taste.
While sauce is simmering, mix cheese ingredients together in a large bowl.
Spread a layer of sauce in the bottom of crockpot. Top with a layer of uncooked lasagna noodles. You may need to break them to fit.
Top noodles with one third cheese mixture. Create layers of sauce, noodles, and cheese mixture. End with a layer of sauce and finally top with your remaining mozzarella and parmesan.
Cover and cook on low for 3 to 3.5 hours or until pasta is cooked through. The edges will be brown and crispy. Turn your crockpot off, open lid slightly to allow steam to escape. Let rest for 30 minutes to allow layers to set.
Notes
Layering Order
1.5 cups of sauce, 2 1/2 to 3 noodles, 1/3 of cheese mixture
1.5 cups of sauce, 2 1/2 to 3 noodles, 1/3 of cheese mixture
1/5 cups of sauce, 2 1/2 to 3 noodles, 1/3 of cheese mixture
Remaining sauce, mozzarella & parmesan
Be sure to let your lasagna rest for up to 30 minutes. This allows it to cool slightly and the layers to set.