Bake the chicken tenders or cutlets on a sheet pan following the package directions, then let them cool briefly. The coating should be cooked and crisp before it goes into the sliders, with no lingering steam trapped around it.

Heat the oven to 350°F and coat a 12x8 inch baking dish with cooking spray; split the slab of rolls and set the bottom half in the dish. A parchment-lined sheet pan also works, but keep the roll slab close together so the sliders do not dry at the edges.

Stir the melted butter with the garlic, onion powder, Italian seasoning or oregano, and crushed red pepper flakes in a small bowl. The mixture should smell strongly of garlic and herbs, with the seasonings evenly dispersed through the butter.

Brush the bottom rolls with garlic butter, then layer on 6 slices mozzarella, 1/2 cup marinara, the chicken, the remaining 1/2 cup marinara, and 1 Tbsp Parmesan; finish with the remaining 6 mozzarella slices. Keep the sauce on top of the cheese and chicken rather than directly on the bread, creating a protected base.

Set the top half of the rolls over the cheese, brush it with the remaining garlic butter, and scatter over the reserved Parmesan. The tops should be coated from edge to edge so they bake into a glossy, savory crust.

Loosely tent the dish with foil and bake for 20 minutes, then remove the foil and bake for 3-5 minutes more. The cheese should bubble along the dish edges and the roll tops should turn lightly golden with a toasted garlic aroma.

Separate the sliders with a sharp serrated knife, cutting along the roll perforations. Use a gentle sawing motion so the cheese stretches without flattening the soft buns.

Warm the additional marinara and place it alongside the sliders for serving. The sauce should be hot enough for dipping but thick enough to cling to each sandwich.