Preheat the oven to 350°F/180°C, and grease a 9×9 or 7×11 inch baking pan/sheet (if you don’t have either, then use 9×13).: When you open the oven and feel the steady warmth, the kitchen starts to change, a soft anticipation sets in that primes you for baking. A properly preheated oven ensures even rising and predictable browning, so take a moment to let it reach the set temperature; the air should feel warm and consistent if you hold your hand briefly near the door, but not too hot to touch. Greasing the pan prevents the slider bottoms from sticking, allowing for a clean release and intact presentation, and the metal of a 9×9 pan encourages gentle conductivity for the cheese to melt evenly. Common mistake to avoid here is skipping preheat or rushing the oven; that can lead to uneven browning or undercooked interiors. If you smell anything acrid as it preheats, double check there is nothing leftover in the oven that could burn.
In a small bowl, combine melted butter and Italian seasoning.: The aroma of warmed butter marrying with dried herbs releases a warm, savory perfume that sets the tone for the topping. Mixing them allows the herbs to hydrate slightly, which helps them adhere to the roll tops and bloom in the oven, producing a toasty, fragrant crust. I like to whisk until the herbs are evenly distributed so there are no clumps, and you can taste a small dab to ensure the seasoning level is right; remember the pepperoni and mozzarella cheese also bring salt, so adjust conservatively. A common error is overheating the butter so it browns too much, giving a nutty or burnt flavor; keep it just melted and warm, not sizzling.
Slice the rolls in half using serrated knife to separate the tops from the bottoms.: The sound of the serrated knife sawing through soft Hawaiian Rolls is satisfying, and doing this carefully keeps the tops intact so they form a neat lid once assembled. Slice with a gentle sawing motion to avoid compressing the bread, and take your time to ensure even halves; uneven slices can lead to some sliders having too much bread or too much filling. If the knife presses down and smashes the roll, the crumb will become dense and won’t absorb the sauce properly. Arrange the bottoms in the pan as soon as they are separated to keep them from drying out.
Place the bottom of the rolls in the pan. Layer half of the cheese, all of the pizza sauce, and then layer the pepperoni. Top with the remaining cheese. Cover with the top buns.: In this stage the visual cues matter, you should see an even blanket of mozzarella cheese hugging the rolls, with glossy pizza sauce in between and neat circles of pepperoni peeking through. The cheese below helps create a cushion that prevents the sauce from soaking directly into the roll bottoms, preserving texture. The pepperoni will release some flavorful oils as it warms, which blend into the cheese and sauce, giving concentrated pockets of savory taste. A frequent misstep is overloading the sauce which leads to soggy bread; apply sauce sparingly and evenly. Also make sure the layers are uniform so every sandwich heats at the same rate.
Brush the herb butter mixture over the tops, cover with foil and bake for 15 minutes. Remove the foil, and bake uncovered for 10 more minutes or until done/golden brown. Watch the sliders so they don’t burn.: Brushing the warm, herb infused butter onto the tops creates a glossy sheen that promotes even browning and herb aroma. Once covered with foil, the steam trapped inside helps the fillings meld and the cheese begin to melt without the tops overbrowning too quickly. You should hear a very gentle hiss of trapped steam as the pan heats, and the kitchen will start smelling faintly of toasted herbs and butter. A common pitfall is skipping the foil which can cause the tops to brown too fast while the centers remain cool. Be careful not to let the butter pool unevenly, or some areas will brown more than others.
Remove the foil, and bake uncovered for 10 more minutes or until done/golden brown. Watch the sliders so they don’t burn.: This final uncovered bake is where the tops crisp and the mozzarella cheese becomes bubbly and slightly golden at the edges. Look for a warm, golden brown color on the buns and small bubbling spots of cheese; that visual cue means the sliders are ready. The scent will deepen into a toasty, slightly caramelized note from the buttered tops, and the pepperoni edges may crisp slightly which adds textural contrast. A typical mistake is leaving them too long which can dry the rolls and make the cheese overly dark; stay nearby during this stage and aim for a gentle, even golden finish. Once out of the oven, let them rest a minute to set, then slice and serve warm.