French Onion Roast Beef Pull-Apart Sandwiches

Ingredients

For the Dressing:

• 1/2 cup mayonnaise
• 1/4 cup chopped dill pickles
• 2 tablespoons ketchup
• 1 tablespoon drained horseradish
• 1/2 teaspoon dried dill
• 1/4 teaspoon onion powder
• Dash of hot sauce
• Kosher salt

For the Sandwiches:

• 6 tablespoons unsalted butter
• 2 large sweet onions, sliced
• 2 teaspoons chopped fresh thyme
• 2 tablespoons dry sherry
• 1 cup low-sodium beef broth
• 1 tablespoon Worcestershire sauce
• Kosher salt and freshly ground pepper
• 1 10-inch oval loaf rye bread
• 12 ounces deli-sliced roast beef
• 6 ounces Swiss cheese, grated

Directions

1. Make the dressing: Mix the mayonnaise, pickles, ketchup, horseradish, dill, onion powder and hot sauce in a small bowl; season with salt. Cover and refrigerate.
2. Make the sandwiches: Preheat the oven to 425˚ F. Line a baking sheet with parchment paper. Melt the butter in a large skillet over medium heat. Pour 4 tablespoons of the butter into a small bowl and set aside. Add the onions and thyme to the skillet with the remaining butter and cook, stirring occasionally, until deep golden, 12 to 15 minutes.
3. Add the sherry to the skillet; cook until evaporated. Add the beef broth and Worcestershire sauce and return to a simmer. Cook until the liquid is reduced by half and the onions are caramelized, 2 to 3 minutes. Season with salt and pepper.
4. Trim the ends off the bread loaf. Cut the bread on an angle into 12 slices, leaving the bottom of the loaf intact. (You can position chopsticks along the long sides of the bread to keep from cutting all the way through the loaf.) Transfer to the baking sheet.
5. Brush the reserved melted butter between the bread slices and all over the loaf. Set aside about one-third of the onions. Fill every other slice of the loaf with the remaining onions, starting with the first slice. Fold the roast beef and tuck into the onion-filled slices, along with the cheese. Top the loaf with the reserved onions and any onion juices.
6. Bake until the cheese is browned and bubbly, about 20 minutes. Pull apart or slice into individual sandwiches. Serve with the dressing.

Link to recipe