If using a sub roll or thicker sandwich bread, slice it open lengthwise. Optionally spread butter on the cut flat surfaces and toast in a skillet or under a broiler until lightly golden, about 1–2 minutes per side; remove and set aside.

Spread & Sauces

In a small bowl combine the mayonnaise (2 tbs), yellow mustard (1 tsp) and garlic sauce (2 tbs). Stir until smooth and uniform. Taste and adjust: add up to 1/2 tsp more mustard for tang or 1/2 tbs more garlic sauce for stronger garlic flavor.

Spread roughly half of the sauce mixture on the bottom half of the bread and the remaining half on the top half to ensure even flavor.

Produce

Prepare tomato

Slice the half tomato into 3–4 thin slices (about 1/4-inch thick). Lay the slices on a paper towel and lightly season with a pinch (about 1/16 tsp) of salt to draw out moisture.

Prepare red onion

Peel and thinly slice the 1/4 red onion into rings or half-rings. If raw onion is strong, soak slices in cold water for 5 minutes, then drain and pat dry.

Prepare lettuce

Wash and dry lettuce. If using whole leaves, tear or fold to fit the sandwich to about 1 cup loosely packed leaves.

Prepare pickle and pepperoncini

If using large dill pickle, slice into two rounds if not pre-sliced. Slice pepperoncini into rings if not pre-sliced, use about 3 rings for mild heat—add more to taste.

Layer the produce onto the bottom bread: first place lettuce (1 cup) as a moisture barrier, then arrange the tomato slices, followed by red onion slices, dill pickle slices and pepperoncini rings. Sprinkle the tomato and lettuce lightly with the remaining salt (up to the specified 1/4 tsp total) and black pepper (about 1/8 tsp) to season.

Final Assembly & Serve

If desired, drizzle 1/2 tsp olive oil over the tomato and lettuce for extra flavor. Close the sandwich with the top bread half (sauce side down).

Cut the sandwich in half on a diagonal or down the middle and serve immediately. If packing to-go, wrap tightly to keep contents together.