In a small bowl combine 1 tablespoon mayonnaise, 2 tablespoons finely minced fresh parsley, 1 tablespoon finely minced cilantro (if using), 1 teaspoon minced fresh oregano (or 1/2 tsp dried), 1 teaspoon minced garlic, 1 teaspoon red wine vinegar, 1 teaspoon extra-virgin olive oil and 1 teaspoon red pepper flakes. Season with 1 teaspoon kosher salt and 1 teaspoon freshly ground black pepper. Stir until smooth and uniformly green. Taste and adjust seasoning — add more vinegar for brightness or more mayo to mellow heat. Set aside for at least 5 minutes so flavors meld.

Sandwich Assembly

Prepare roll

If you prefer a slightly toasted roll, split the hoagie roll lengthwise without cutting all the way through. Lightly butter the cut sides with the softened unsalted butter (about 1 teaspoon). Place buttered sides down in a skillet over medium heat for 1–2 minutes until lightly golden, or toast under a broiler for 30–60 seconds — watch carefully to prevent burning. Remove and keep warm.

Layer cheese and beef

On the bottom half of the warm roll, place the 3 slices of aged provolone cheese in a single layer. Pile 6 ounces of thinly sliced roast beef on top of the cheese. If the roast beef is cold and you prefer it warmed, place the sandwich (open-faced) under a broiler for 30–60 seconds just until the cheese begins to melt. Remove from heat.

Add tomato and pickles

Arrange thin slices from 1 Roma tomato over the beef. Add 4 lengthwise slices (or chips) of cold-packed dill pickle across the tomato. If using pickled banana peppers or hot peppers, add to taste on top of the pickles.

Apply chimichurri mayo and finish

Spread the prepared chimichurri mayo (use all or about 1 tablespoon, according to taste) on the top half of the roll. Close the sandwich and press gently to compact layers. Slice the sandwich in half, serve immediately, and enjoy.