01 -
Heat 2 tablespoons butter in a skillet over medium heat. Add chopped onions and cook until translucent and tender. Stir in minced garlic during the last 2 minutes and cook until fragrant. Remove from heat and set aside.
02 -
Preheat oven to 350°F. Using a long serrated knife, slice slider rolls horizontally, keeping the bottom halves intact. Arrange rolls in a foil-lined 9 x 13 inch baking dish or on a baking sheet lined with foil or non-stick liner.
03 -
Combine mayonnaise and horseradish in a small bowl. Evenly spread the mixture over the bottom halves of the rolls.
04 -
Layer half of the roast beef slices over the sauce, folding slices to fit neatly. Place 6 slices of provolone cheese over the roast beef. Repeat the layers with the remaining roast beef and cheese. Spread the sautéed onion and garlic mixture over the top cheese layer.
05 -
Place the top halves of the slider rolls over the assembled layers to complete the sandwiches.
06 -
In a small bowl, mix melted butter with Worcestershire sauce, Dijon mustard, and poppy seeds. Using a spoon or basting brush, evenly coat the top of the assembled sliders with the glaze.
07 -
Bake in the preheated oven for 10 to 15 minutes, or until the sliders are heated through and the cheese is melted.