Red and Green Stuffed Shells recipes

Name: Red and Green Stuffed Shells recipes
Ingredients: 1 Tablespoon Olive Oil; 1/2 whole Onion, Diced; 1 clove Garlic, Minced; 10 ounces, weight Fresh Baby Spinach; 4 Tablespoons Butter; 1/4 cup All-purpose Flour; 2-1/2 cups Whol Milk, More If Needed; 2 Tablespoons Chopped Basil; 2 Tablespoons Chopped Parsley; salt; pepper; 30 ounces, weight Whole Milk Ricotta Cheese; 1 cup Grated Parmesan Cheese, Plus More For Sprinkling; 1 whole Large Egg; 12 ounces, weight Jumbo Pasta Shells (25 To 30 Shells) Cooked Until Slightly Firmer Than Al Dente