This is a tomato pie with a little more zip than the traditional.
Preheat oven to 400 degrees F (200 degrees C).
Press pie crust pastry into a 9-inch pie pan; sprinkle with 1/2 cup Parmesan cheese. Dip tomato slices in flour, coating both sides. Arrange a layer of coated tomato slices atop the Parmesan cheese. Top with half the onion, half the basil, half the salt, and half the black pepper. Repeat layering with 1/2 cup Parmesan cheese and remaining tomatoes, onion, basil, salt, and black pepper, ending with 1/2 cup Parmesan cheese.
Stir mustard and mayonnaise together in a bowl. Spread over Parmesan cheese layer.
Bake in the preheated oven until cheese is melted and bubbling, about 25 minutes.
Per Serving: 366 calories; protein 11.1g; carbohydrates 28g; fat 23.2g; cholesterol 21.1mg; sodium 1212.3mg.