Prime Rib Sliders [thursdays Only] Recipe

Prepare horseradish mayonnaise

In a small bowl combine 1 cup mayonnaise, 2 tablespoons prepared horseradish, 1 teaspoon Dijon mustard, 1 teaspoon Worcestershire sauce, 1/2 teaspoon salt and 1/2 teaspoon freshly ground black pepper. Stir until smooth, taste and adjust horseradish or salt. Cover and refrigerate until assembly.

Warm prime rib and au jus

If using leftover roasted prime rib, slice thin (about 1/8–1/4"). Place slices in a shallow ovenproof dish, pour 1 to 1 1/2 cups warm au jus over meat to keep moist. Cover tightly with foil and heat in a 325°F (165°C) oven for 10–15 minutes until warmed through but not overcooked. Alternatively, warm slices briefly in a skillet with au jus over medium heat for 2–4 minutes, turning once.

Keep au jus warm in a small saucepan over low heat for serving; reheat gently if necessary and skim any solids.

Make garlic butter and prepare rolls

Preheat oven to 350°F (175°C). In a small bowl mash together 4 tablespoons softened unsalted butter, 1 teaspoon minced garlic and 1 tablespoon finely chopped parsley until combined. Split the 12 slider rolls horizontally, keeping top and bottom connected if they come in a single sheet, and place bottoms on a baking sheet.

Butter tops and toast

Spread half of the garlic butter mixture over the inside of the top halves and the remaining butter over the bottom halves. Sprinkle 1/2 teaspoon coarse kosher salt evenly over the buttered tops. Place assembled rolls (open-faced) in the preheated oven and bake 6–8 minutes until butter is melted and edges are lightly golden. Remove from oven.

Caramelize onions (if not prepared)

Thinly slice 2 medium onions (not included in ingredient list — approx. 1 1/2 cups when finished) and cook in a skillet over medium-low heat with 1 tablespoon butter or oil and a pinch of salt, stirring occasionally, for 25–30 minutes until deep golden and sweet. Deglaze with 1 tablespoon water or balsamic vinegar at the end if they stick. Set aside 1 cup for sliders.

Assemble sliders

On the bottom halves of the warm rolls, spread about 1 tablespoon horseradish mayonnaise per slider. Arrange warm thin slices of prime rib on top, roughly 2 ounces (about 1/4 cup by volume) of meat per slider, overlapping as needed. Add a spoonful (about 1 tablespoon) of caramelized onions to each, then place a half-slice of cheese over the meat (use a whole slice folded if necessary). Add a few slices of pickled pepperoncini or pickle and a small handful of arugula if using.

Finish and melt cheese

Place the full assembled sliders (tops on) back into the oven at 350°F (175°C) for 3–5 minutes, or under a broiler for 1–2 minutes, until cheese is melted and rolls are warmed through. Watch closely to prevent burning.

Serve with au jus

Remove sliders from oven and cut between rolls into individual sandwiches if baked as a sheet. Serve immediately while hot with warm au jus on the side for dipping (about 2 tablespoons au jus per slider).