Preheat oven to 375°F (190°C), roll out pie crust into 9-inch dish, prick bottom with fork, blind-bake for 8-10 minutes until lightly golden, set aside to cool.

Cook thick-cut bacon in skillet over medium heat until crispy, about 8-10 minutes, transfer to paper towel-lined plate to drain, crumble once cooled.

In the same skillet, add sliced onions with reserved bacon drippings, cook over medium-low heat for 10-15 minutes until golden brown.

Slice firm, ripe tomatoes, lay on paper towels, sprinkle with salt, let sit for 10 minutes to draw out moisture.

Layer half the crumbled bacon, half the caramelized onions, and a layer of tomato slices in the prepped crust, repeat with remaining ingredients.

Combine mayonnaise, cheddar cheese, mozzarella cheese, and fresh herbs in a bowl, mix well, and spread over layered ingredients in pie crust.

Bake pie for 30-35 minutes until cheese topping is bubbly and lightly golden, let rest for 10 minutes before slicing and serving.