Cheesy Stuffed Shells | America's Test Kitchen

Ingredients

• 2 tablespoons extra-virgin olive oil
• 1 onion , chopped
• 1/2 teaspoon salt
• 1/2 teaspoon pepper
• 6 garlic cloves , minced
• 1/4 teaspoon red pepper flakes
• 1 (28-ounce) can tomato puree
• 2 cups water
• 1 teaspoon sugar
• 10 ounces (1¼ cups) whole-milk ricotta cheese
• 4 ounces fontina cheese , shredded (1 cup)
• 2 ounces Pecorino Romano cheese , grated (1 cup)
• 2 large eggs
• 3 tablespoons chopped fresh basil
• 1 1/2 tablespoons cornstarch
• 2 garlic cloves , minced
• 1 teaspoon dried oregano
• 25 jumbo pasta shells
• 8 ounces fontina cheese , shredded (2 cups)
• 1 tablespoon chopped fresh basil