Preheat your oven to 400 degrees. On a baking sheet lined with parchment paper, layer on your bacon in a single layer. Transfer to the oven for 15 to 20 minutes, flipping halfway, until the bacon is cooked through, with your desired crunch. It will continue to cook when you take it out of the oven, so take it out 1 to 2 minutes before you think it's done.
In the meantime, slice your tomatoes on a cutting board, about 1/2 inch thick, and season with salt and pepper.
Toast your bread, if preferred, and set up your station with the iceberg leaves.
Assemble your sandwich! With the bacon still hot, start to assemble. Spread an even layer of your basil mayo on the bread, about 1 to 2 tablespoons each sandwich, then top with the tomatoes, and iceberg, finishing with your bacon, and topping with your bread, also with more basil mayo spread on the top slice. Slice in half and eat immediately.
Notes
Season your Tomatoes: A sprinkle of salt with go a long way ahead of time to bring out the tomato's natural sweetness and help to not have a soggy sandwich.
Bread Options: Use any of your favorite sliced bread, such as sourdough, ciabatta, or whole-grain.
Bacon Alternatives: You can use other alternatives like turkey bacon, or crispy tempeh to make this vegetarian.