Preheat oven to 400°F (200°C). Line a rimmed baking sheet with aluminum foil for easy cleanup. Place a wire rack on the sheet if you have one — this lets fat drip away and bacon crisp evenly on both sides.

Lay bacon slices in a single layer on the rack or directly on foil. They should not overlap. Place in the cold oven? No — always start bacon in a preheated oven for predictable rendering.

Bake for 14-18 minutes. Check at 14 minutes: bacon should be deep golden brown but not dark. If you prefer chewier slices, pull at 14. For shatter-crisp, go to 18. Transfer bacon to a paper-towel-lined plate. The bacon will continue to crisp slightly as it cools.

While bacon bakes, wash and dry the tomato. Slice off the top and bottom — just a thin disc — then cut the tomato into 4 even slices, about 1/3-inch thick. Lay slices on a paper towel for 2 minutes; this removes excess moisture that would make your bread soggy. Sprinkle very lightly with flaky salt.

Wash and dry lettuce leaves. Pat them bone-dry with a kitchen towel. Any water left on lettuce will dilute the mayo and soften the bread.

Toast bread slices until golden — I use a toaster on medium, but a broiler works too. Toast until the surface is dry and just starting to color, about 2 minutes per side. Let cool 30 seconds.

Spread 1 heaping tablespoon of mayonnaise on each slice of bread. Go edge to edge — this creates a moisture barrier. Season the mayo on the bottom slice with a twist of black pepper.

Assemble: On the bottom slice (peppered mayo side up), layer 2 tomato slices. Place 2 lettuce leaves on top of the tomato, folding them to fit. Arrange 4 bacon slices on the lettuce, breaking them to fit if needed. Close with the top slice, mayo side down.

Press gently with the palm of your hand to settle the layers. Slice diagonally with a serrated knife — a clean, sawing motion prevents squishing. Serve immediately.