Slow Cooker Lasagna

Name: Slow Cooker Lasagna
Prep time: 20 min
Cook time: 5 h
Total time: 5 h
Yield: 6-8
Ingredients: Ingredients; 1 lb ground beef (or Italian sausage); 1 small onion, diced; 3 cloves garlic, minced; 1 jar (24 oz) marinara sauce; 1 can (15 oz) tomato sauce; 1 teaspoon Italian seasoning; Salt and black pepper, to taste; 12 lasagna noodles, uncooked; 2 cups ricotta cheese; 2 cups shredded mozzarella cheese; 1/2 cup grated Parmesan cheese; 1 egg, beaten; 2 cups fresh spinach, chopped (optional); 2 cups shredded mozzarella cheese (for topping); Fresh basil or parsley, chopped (for garnish)