Roast Beef Melt Recipe

Cook onions

Thinly slice 1 large yellow onion (about 1 to 1 1/2 cups sliced). Heat 1 tsp olive oil and 1 tbsp butter in a medium skillet over medium-low heat. Add onions and a pinch (about 1/8 tsp) of salt. Cook, stirring every 3–4 minutes, for 20–25 minutes until onions are deeply golden and sweet. If they begin to stick, add 1–2 tbsp water to deglaze. Set aside 1 cup caramelized onions for sandwiches.

In a small bowl combine 4 tbsp mayonnaise, 2 tsp Dijon mustard, 1 tbsp prepared horseradish, 1 tsp Worcestershire sauce, and 1 tsp lemon juice. Whisk until smooth and season to taste with a pinch of salt and pepper. Adjust horseradish or mustard for heat. Set aside.

Heat a large skillet or griddle over medium heat. Spread about 1/2 tbsp softened butter on the outer face of each bread slice (total 2 tbsp for four sandwiches).

Turn bread, and on the inner face of two slices spread about 1 tbsp of the prepared sauce each. Divide the roast beef evenly (about 2 oz per sandwich) and pile it onto the two sauced slices.

Season the roast beef lightly with the remaining 1/2 tsp salt and 1/4 tsp black pepper, then top each with about 1/4 cup caramelized onions and 4 pickle slices (2 per sandwich half).

Layer 1 slice Swiss cheese and 1 slice provolone (if using) over the beef and onions on each sandwich. Close sandwiches with the buttered outer bread slices, buttered side out.

Place each sandwich in the preheated skillet. Press gently with a spatula or a heavy pan and cook 3–4 minutes per side, or until bread is golden brown and cheese is melted. If cheese is slow to melt, cover the skillet for 1–2 minutes to trap steam.

Transfer sandwiches to a cutting board, let rest 1 minute, then cut in half and serve immediately.

While sandwiches cook, for dipping au jus heat 1 cup beef broth with 2 tbsp red wine (optional) and 1/2 tsp beef drippings or base in a small saucepan over medium heat. Bring to a gentle simmer, taste and adjust seasoning with salt and pepper. Keep warm and serve alongside sandwiches for dipping.