Lay both bread slices out flat. Spread mayo edge-to-edge on one slice as a moisture barrier for the vegetable side. Spread mustard edge-to-edge on the other slice as a tang barrier for the pickle side, keeping the two flavor zones distinct.

On the mayo side, layer the lettuce first so it sits directly against the bread as an extra moisture shield, then shingle the tomato on top. Season lightly with salt and pepper.

Fold and shingle the roast beef over the tomato, then the turkey over that. Folding instead of laying the slices flat adds air and height so each bite has texture instead of a dense meat slab.

Lay the cheese on top of the turkey, centered so it's the last thing touching the mayo-and-vegetable stack before the pickle takes over.

Lay the pickle planks over the cheese, then close the sandwich with the mustard-side bread, mustard-side down against the pickles so the acid-and-tang cluster stays together.

Press down gently to set the layers, then slice in half on a slight diagonal with a sharp serrated knife in one smooth stroke. Stand one half on top of the other, cut side facing out, for the classic tall cross-section shot.