Ingredients

• 1 recipe pastry for a 9-inch single pie crust
• ½ cup grated Parmesan cheese
• 2 large tomatoes, seeded and sliced
• 3 tablespoons all-purpose flour
• 1 sweet onion (such as Vidalia®), minced
• ½ cup chopped fresh basil
• ½ teaspoon salt
• ½ teaspoon ground black pepper
• 1 cup grated Parmesan cheese, divided
• ½ cup Dijon mustard
• ¼ cup mayonnaise