Wash and dry the lettuce leaf. Slice the tomato into two even 1/4-inch slices. Peel and cut onion into thin rings. If pickle is whole, slice into 3 thin rounds per sandwich.

Toast bread (optional)

If you prefer a warm, slightly crisp sandwich, spread butter lightly on the outer sides of each bread slice. Heat a skillet over medium heat and toast each buttered side until golden, about 1-2 minutes per side. Alternatively, use a toaster or sandwich press.

Spread condiments

Place the bread slices with inner sides up. Spread 1 tablespoon mayonnaise evenly on one slice. Spread 1 teaspoon mustard evenly on the other slice. Use more or less to taste.

Layer sandwich

On the mayonnaise-covered slice, place the lettuce leaf first (this helps keep bread from getting soggy). Top with the two tomato slices, then season the tomato lightly with 1/4 teaspoon salt and a pinch (about 1/8 teaspoon) black pepper. Add the 3 onion rings and 3 pickle slices. Place the 4 slices of ham in a single even layer (fold if needed for height) on top of the pickles/onion. Finish the stack with 1 slice of your chosen cheese.

Close and serve

Place the mustard-spread bread slice on top, mustard side down. Press gently to compact the sandwich. If desired, cut the sandwich in half diagonally or down the middle. Serve immediately. If you toasted the bread and want the cheese melted, after assembling place the sandwich in a warm skillet or sandwich press for 1-2 minutes per side over low-medium heat until the cheese softens.