These over-the-top sliders come together in under 30 minutes thanks to John Soules Foods’ Sliced Beef Steak. The extra-thin, tender beef is piled on cushy buns and topped with all of the fixins of a Chicago-style Italian beef hoagie. Did we mention you can also make these sliders in advance? Assemble the mini-sandwiches in the baking dish and then pop in the refrigerator until you’re ready to bake. Serve them as a crowd-pleasing party bite or for dinner with a side of beef au jus for dipping.
Preheat the oven to 350° and grease a 9-by-13-inch baking dish or quarter-size rimmed sheet pan.
In a small bowl, whisk the mayonnaise with the horseradish and Worcestershire. Season with salt and pepper. Add more horseradish, if desired.
Arrange the bottom halves of the dinner rolls in the baking dish, cut side up. Spread with half of the horseradish mayo. Top each roll with a few slices of beef and ½ slice of folded provolone cheese. Divide the giardiniera among the sliders. Spread the remaining horseradish mayo on the cut sides of the top buns and close the sliders.
Brush the tops with melted butter and sprinkle with flaky sea salt. Bake the sliders until golden brown on top and the cheese is melted, 15 to 20 minutes. Let cool slightly before serving.