lasagna recipe with ricotta cheese

Lasagna Recipe with Ricotta Cheese Ingredients: 12 lasagna noodles 1 lb ground beef or ground turkey 1 jar (24 oz) marinara sauce 1 container (15 oz) ricotta cheese 2 cups shredded mozzarella cheese 1/2 cup grated Parmesan cheese 1 large egg 2 cups baby spinach (optional) Salt and pepper, to taste