Stacked Roast Beef and Tartar Sauce Sandwiches

Arrange a single layer of pickles on two of the toasted bread slices. Layer with half of the roast beef, followed by the remaining pickles and remaining roast beef. Season to taste with salt and pepper. Arrange lettuce leaves over the roast beef, followed by a generous dollop of tartar sauce and sliced red onion; close sandwich, cut in half and secure sandwich halves with wooden picks. Serve with potato chips.