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a plain plate holding one large closed square buttermilk-biscuit sandwich with thin roast-beef slices and brown onion-mustard gravy visible between the biscuit halves, without mashed potatoes or garnish
Rachel Kim

Hot Roast Beef Sandwich with Gravy

A large buttermilk biscuit gives hot roast beef and onion gravy a different kind of dinner plate, with a tender middle that catches the sauce and a browned top that still has some structure. Cook the onions slowly before adding flour, then warm the leftover beef only after the gravy is ready so the slices don’t spend half an hour boiling while you wait for the biscuits.
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Prep Time 25 minutes
Cook Time 45 minutes
Total Time 1 hour 10 minutes
Servings: 4
Ingredients Method

Ingredients
  

  • 2 cups all-purpose flour 250 g, plus 2 tbsp for the gravy
  • 1 tbsp baking powder
  • 3/4 tsp fine salt divided
  • 6 tbsp cold unsalted butter cubed, plus 2 tbsp for the gravy
  • 3/4 cup cold buttermilk
  • 1 large yellow onion thinly sliced
  • 2 cups low-sodium beef stock
  • 1 tbsp whole-grain mustard
  • 1/4 tsp black pepper
  • 1 lb leftover cooked roast beef thinly sliced

Method
 

  1. Heat oven to 425°F and line a sheet pan with parchment. Mix 2 cups flour, baking powder and 1/2 teaspoon salt, then rub in the cold cubed butter until mostly pea-sized pieces remain.
  2. Stir in buttermilk just until the dough holds together. Pat into a 7-inch square about 1 inch thick, cut into four equal square biscuits and place about 2 inches apart on the pan.
  3. Bake for 17 to 20 minutes until risen and golden. Meanwhile, melt the remaining 2 tablespoons butter in a skillet over medium-low heat and cook onion for 18 to 20 minutes until soft and golden.
  4. Stir the remaining 2 tablespoons flour into the onions for 1 minute. Gradually add stock, mustard, remaining salt and pepper and simmer for 5 to 7 minutes until the gravy coats a spoon.
  5. Fold roast beef into the gravy and warm gently for 5 to 8 minutes until the meat reaches 165°F. Split the biscuits horizontally without crushing their layers.
  6. Divide hot beef and a modest spoonful of onion gravy among the biscuit bottoms, then replace the tops. Serve one large closed biscuit sandwich per person, with any extra gravy added at the table only as wanted.