Step 1

In a small bowl, combine 2 tablespoons salt, sugar, crushed peppercorns and garlic.

Step 2

Rub the brisket rub onto all sides of the brisket. Cover and refrigerate for eight hours or overnight.

Step 3

In a small bowl, stir together the mayonnaise, blue cheese, horseradish and cayenne. Refrigerate until you’re ready to assemble the sliders.

Step 4

Place the carrots, chopped onions and celery in a 6- or 7-quart slow cooker. Place the brisket on top of the vegetables.

Step 5

In a small bowl, combine the red wine, mustard and bay leaves. Pour the mixture over the brisket. Cook, covered, on low for seven to nine hours or until the meat is fork-tender.

Step 6

Meanwhile, in a large skillet, heat the oil over medium heat. Add the onions and the remaining salt. Cook and stir until softened. Reduce the heat to medium-low. Cook for 30 to 35 minutes or until deep golden brown, stirring occasionally. Editor's Tip: Caramelized onions are different from sauteed onions. Sauteed onions cook pretty quickly. They might be softened and slightly browned, but they still retain a sharp onion flavor. Caramelized onions, however, enjoy an extended cooking time, which lets the onion's natural sugars brown. Caramelized onions have a deep color and a super-sweet flavor.

Step 7

Remove the brisket, and allow it to cool slightly. Reserve 1 cup cooking juices, and discard the remaining juices. Skim the fat from reserved juices. Thinly slice the brisket across the grain.

Step 8

Return the sliced brisket to the slow cooker. Pour the juices over the brisket.

Step 9

Arrange the brisket on buns with the blue cheese mayonnaise and caramelized onions. If desired, add arugula and tomato slices.