Set the oven to 350°F (175°C), cut horizontally through the connected rolls, and settle the lower slab into a baking dish. Keep the knife level so the bottom bread has an even thickness to support the filling.
Distribute the salami across the bread, follow with pepperoni and turkey, then cover with provolone and replace the upper roll slab. Even layers keep the filling balanced instead of creating a thick mound in the middle.
Stir the melted butter with the minced garlic clove, additional minced garlic, listed salt, and parsley, then brush the mixture across the roll tops. Spread the garlic pieces around so each roll gets a glossy coating rather than one concentrated patch.
Form a loose foil tent over the baking dish and bake for 20 minutes, checking that the filling is hot and the provolone has melted. Look for softened, slightly translucent cheese edges and a fragrant garlic aroma while the foil shields the sweet bread from excessive browning.
During baking, whisk the mayonnaise with mustard, vinegar, garlic powder, red pepper flakes, and dried parsley, then fold in the pepperoncini, onion, and lettuce near the end of the bake. The dressing should coat the shreds evenly, with the lettuce still crisp rather than collapsed.
Lift off the warm top slab, drizzle the honey over the exposed meat and cheese, and distribute the freshly dressed salad across the filling. A level salad layer gives every slider cool crunch without a bulky pile pushing the bread apart.
Return the top slab, scatter Parmesan over it, and cut along the roll divisions to serve immediately while warm. The finished sliders should have soft, buttery bread, melted cheese, and a distinctly cool, crisp center.