Step 1: Preheat your oven to 350°F (175°C). Lightly warm the sub rolls for 2-3 minutes until soft, but not toasted. Split each roll open lengthwise, leaving a hinge intact.
Step 2: Spread a thin, even layer of mayonnaise on one half of the roll and yellow mustard on the other half.
Step 3: Layer the thinly sliced honey roast ham evenly over the bottom half of each roll.
Step 4: Place one slice of Swiss cheese over the ham on each sub.
Step 5: Add one iceberg lettuce leaf, 2 slices of fresh tomato, thin rings of red onion, and 2-3 dill pickle slices (if using) onto each sub.
Step 6: Season lightly with salt and pepper to taste. Carefully close the rolls.
Step 7: Wrap each assembled sub securely in aluminum foil. Place the wrapped subs on a baking sheet.
Step 8: Bake in the preheated oven for 5 minutes. Carefully unwrap the subs and return them to the oven for another 2-3 minutes, just until the cheese is melted and gooey.
Step 9: Remove from oven, let rest for 1 minute to allow the flavors to meld, then serve immediately while warm.