In a small bowl, combine mayonnaise, Dijon mustard, olive oil, red wine vinegar, dried oregano, salt, and black pepper. Whisk until smooth and emulsified. Taste and adjust salt or vinegar to preference.

Prepare vegetables and bread

Wash and dry lettuce leaves. Slice tomato into 3 even slices and thinly slice red onion into rings. If using basil, pick and rinse leaves and pat dry.

Slice roll horizontally. If you prefer a warm/toasted sandwich, butter or brush the cut faces of the roll lightly with softened butter or olive oil.

Optional: Toast the roll cut-side down in a skillet over medium heat (about 1–2 minutes) or under a broiler for 1–2 minutes until lightly golden.

Assemble sandwich

Spread half of the prepared sandwich spread evenly on the bottom half of the roll and the remaining spread on the top half.

Layer provolone cheese on the bottom half of the roll first. This helps protect the bread from moisture.

Arrange 6 slices of Genoa salami over the provolone, slightly overlapping. For a meatier sandwich, add more slices to taste (common is 6–10 slices).

Top the salami with tomato slices, red onion rings, pepperoncini slices, and lettuce. Tuck basil leaves in if using.

Close the sandwich, press gently to compact, and cut in half on a diagonal if desired. Serve immediately.

Serving suggestions

Serve with a side of pickles, kettle chips, or a simple green salad. For a deli-style touch, drizzle a little extra olive oil and a sprinkle of oregano on the tomatoes before closing the sandwich.