01 -
Melt 2 tablespoons of butter in a skillet over medium heat. Add chopped onions and cook until softened. Stir in minced garlic during the final minutes and sauté together until fragrant. Remove from heat and set aside.
02 -
Preheat the oven to 350°F. Using a long serrated knife, carefully slice the slider rolls in half horizontally. Arrange the bottom halves inside a foil-lined 9x13-inch baking dish or on a baking sheet lined with non-stick foil.
03 -
In a small bowl, mix together mayonnaise and horseradish until well combined. Evenly spread the mixture over the cut side of the bottom half of the slider rolls.
04 -
Distribute half of the roast beef evenly over the horseradish mayo layer. Top with six slices of provolone cheese, then repeat the layers with the remaining roast beef and provolone cheese slices.
05 -
Spread the warm sautéed onions and garlic evenly over the final layer of cheese. Place the tops of the slider rolls to complete each sandwich.
06 -
Melt 5 tablespoons of butter in a small bowl. Stir in Worcestershire sauce, Dijon mustard, and poppy seeds. Using a basting brush or spoon, evenly coat the tops of the slider rolls with the glaze.
07 -
Place the assembled sliders in the preheated oven and bake for 10 to 15 minutes until heated through and the cheese is melted. Remove from oven and serve warm.