"The miniature version of the ultimate hamburger—grilled patties of ground wagyu beef served with caramelized shallots on toasted brioche. "
For the Caramelized Shallots
2 tablespoons (1/4 stick) unsalted butter
1 tablespoon extra-virgin olive oil, or more butter
1 pound shallots, peeled and thinly sliced crosswise
Coarse salt (kosher or sea) and freshly ground black pepper
For the Sliders
1 1/2 pounds ground wagyu or Kobe-style beef, ideally with a fat content of 15 to 20 percent
Coarse salt (kosher or sea) and freshly ground black pepper
12 small brioche rolls or Parker House rolls
2 tablespoons (1/4 stick) unsalted butter, melted
Sliced dill pickles or sweet pickles (optional)
Make the caramelized shallots: Melt the butter in the olive oil in a heavy saucepan over medium heat. Add the shallots and cook until the shallots have been reduced to a dark, thick, sweet paste, 15 to 25 minutes; you will have to stir the shallots often. Lower the heat as needed to keep the shallots from burning. Season the shallots with salt and pepper to taste. The shallots can be caramelized several hours or even a day ahead and refrigerated, covered. Let them return to room temperature before using.
Make the sliders: Lightly wet your hands with cold water and divide the beef into 12 portions, then form each portion into a square patty about 2 inches square and ½ inch thick. Place the beef patties on a plate lined with plastic wrap and refrigerate them, covered, until you are ready to grill.
Set up the grill for direct grilling and preheat it to high. Ideally you’d grill over oak or another hardwood fire.
When ready to cook, brush and oil the grill grate. Generously salt and pepper the beef patties and place them on the hot grate. Grill the sliders until cooked to taste, 2 to 3 minutes per side for medium, turning them with a spatula.
Brush the cut sides of the rolls with the melted butter and grill them until golden brown, 2 minutes. Watch the buns; they will burn quickly.
To assemble the sliders, place a spoonful of caramelized shallots on the bottom half of each bun. Top each with a slider, a slice of pickle, if desired, and the top of the bun and serve at once.