Update your lunch routine with this new spin on the classic BLT. Mr. Stripey tomatoes are a variety of heirlooms with pale, yellow skins with a pinkish-orange blush, occasionally with green stripes. Substitute a beefsteak or other large, firm tomato. Pancetta is Italian cured bacon that gets cooked in the oven (no splattering on the cook-top). Substitute regular cured bacon, if desired. Prepare the mayonnaise mixture and cook the pancetta up to one day ahead.