Comforting Crockpot Bowtie Casserole with Beef and Cheese

Ingredients

• 1 lb ground beef, 80% lean
• 1 medium yellow onion, chopped
• 2 cloves garlic, minced
• 1 can (14.5 oz) stewed tomatoes, unsweetened
• 1 can (8 oz) tomato sauce
• 1/2 tsp dried oregano
• 1 tsp Italian seasoning
• 1/2 tsp salt, or to taste
• 1/4 tsp black pepper, freshly ground
• 2 cups fresh spinach or 1 cup thawed frozen spinach, squeezed dry
• 3 cups cooked bowtie pasta, al dente
• 1/4 cup grated Parmesan cheese
• 1 cup shredded mozzarella cheese, divided