Place halved potatoes in a bowl. Add 2 tbs olive oil, 1 tsp garlic powder, 1 tsp smoked paprika, 1 tsp salt, and 1/2 tsp black pepper. Toss until evenly coated.

Roast potatoes

Spread potatoes cut-side down on the prepared baking sheet in a single layer. Roast in the preheated oven for 25–30 minutes, turning once halfway, until golden and tender when pierced with a fork.

Finish

Remove from oven, taste and adjust seasoning. Sprinkle 1 tbs chopped fresh parsley over potatoes if using. Keep warm while you prepare the sandwiches.

Sandwich

Cook bacon

Place bacon in a cold skillet in a single layer. Cook over medium heat, turning occasionally, until crisp and browned, about 8–12 minutes depending on thickness. Alternatively, bake bacon on a rimmed sheet at 200°C (400°F) for 12–18 minutes. Transfer bacon to a paper-towel-lined plate to drain.

Prepare produce and bread

While bacon cooks, slice the tomato into 4 even slices. Tear or trim lettuce leaves to sandwich-sized pieces. Lightly toast the 4 slices of bread until just golden.

Season tomato

Arrange tomato slices on a plate and sprinkle with about 1/4 tsp salt and a light dusting of black pepper (from the measured salt and pepper in ingredients). This is included in the ingredients totals.

Assemble sandwiches

Spread 1 tbs mayonnaise on one side of each toast slice (4 tbs total). On two slices of toast (bottom slices), layer: 2 slices of bacon, 2 tomato slices, 2 lettuce leaves. Top each with the remaining toast slice, mayo side down. If desired, add the remaining 2 bacon slices inside for an extra-meaty BLT (quantities provided assume 4 slices per sandwich pair).

Slice and serve

Cut each sandwich in half on the diagonal or down the middle. Serve immediately with the warm roasted potatoes on the side.