Spinach and Ricotta Stuffed Shells

Name: Spinach and Ricotta-Stuffed Shells
Ingredients: 1 20 jumbo pasta shells (about half a 12-ounce box); 1 24-ounce jar marinara sauce; 2 15-ounce containers ricotta; 2 cups cups baby spinach, chopped; 1/2 cup grated Parmesan (2 ounces); 1/2 cup grated mozzarella (4 ounces); kosher salt and black pepper; 1 Clove of garlic, minced