01 -
Preheat the oven to 350°F (175°C).
02 -
In a skillet over medium heat, cook the sliced onions in a spoonful of bacon drippings until soft and golden, about 10 minutes. Allow to cool slightly.
03 -
In the pre-baked pie crust, arrange half the caramelized onions, then half the tomato slices, and half the crumbled bacon. Repeat with the remaining onions, tomatoes, and bacon.
04 -
In a small bowl, combine shredded mozzarella cheese, mayonnaise, sour cream, all-purpose flour, garlic powder, black pepper, and salt until fully incorporated.
05 -
Spread the cheese mixture evenly over the layered filling. Position the dish on a baking sheet and bake for 35 to 40 minutes, or until the topping is golden brown and bubbling.
06 -
Allow the pie to rest for several minutes before slicing. Garnish with chopped fresh chives or parsley if desired.