Preheat your oven to 375°F (190°C). Fit the refrigerated pie crust into a 9-inch pie pan, then prick it with a fork to prevent puffing. Blind-bake for 8–10 minutes, or until lightly golden.

In a skillet over medium heat, fry the bacon until it’s crispy and golden. Remove it from the pan, crumble it into pieces, and set aside. Don't forget to reserve 1 tablespoon of those tasty drippings!

Using the same skillet and the reserved bacon drippings, add the sliced onions. Cook them over medium-low heat for about 10–15 minutes, stirring occasionally until they're soft and golden brown.

Slice your tomatoes and sprinkle them with salt. Let them sit for about 10 minutes, then pat dry with paper towels to remove excess moisture.

In the pre-baked pie crust, layer half of the crumbled bacon, half of the caramelized onions, and half of the tomato slices. Repeat these layers with the remaining ingredients.

In a bowl, combine the mayonnaise, shredded cheddar, mozzarella, and chopped fresh basil (or dried). Spread this mixture evenly over the top of the assembled pie.

Place the pie in the oven and bake for 30–35 minutes, or until the topping is bubbly and golden brown.

Let it rest for about 10 minutes before slicing.

Garnish your delicious pie with fresh basil or parsley.