If you prefer toasted bread, spread butter thinly on one side of each slice. Heat a skillet over medium heat and toast the buttered side of each slice 1–2 minutes until golden. Alternatively, toast in a toaster until lightly browned. Place toasted or untoasted slices on a cutting board, butter/toast side down.

Apply spreads

On one slice, spread 1 tablespoon mayonnaise evenly to the edges. On the other slice, spread 1 teaspoon mustard evenly. Adjust amounts to taste.

Meat

Arrange the 3 oz of chosen deli meat in an even layer on top of the mayonnaise-spread slice. If using thicker roast beef or carved meat, fold slices slightly to create loft and prevent a flat sandwich.

Cheese

Place the chosen cheese slice directly on top of the meat. If you prefer melted cheese, place the open-faced sandwich under a broiler for 30–60 seconds or return to the hot skillet, cover briefly until it softens/melts.

Vegetables & extras

Top the cheese with the lettuce leaf, then the two tomato slices. Lightly sprinkle the tomato with about 1/4 teaspoon salt and 1/8 teaspoon black pepper to enhance flavor.

Add the thin red onion slices and 3 pickle slices on top of the tomato. Adjust placement so the sandwich balances and won't slide when picked up.

Assembly & finishing

Carefully place the mustard-spread slice of bread (mustard side down) on top of the stacked ingredients, aligning edges. Press gently but firmly to compress slightly so the sandwich holds together.

If desired, secure the sandwich with a toothpick or cut it in half diagonally or down the middle. Serve immediately. If packing for later, wrap tightly in cling film or parchment and refrigerate up to 24 hours.