In a colander, drain the liquid from the sauerkraut, pressing down to get as much moisture out as possible. Transfer the sauerkraut to a plate lined with a double thickness of paper towels. Reserve

Heat a large skillet on medium high heat, split each slider bun in half, butter each side and add to the skillet to toast slightly. Or alternatively, arrange them on a baking sheet, cut side up and slide them under a preheated broiler to toast. When cool, spread mustard on both sides of each slider bun. Add 1 or 2 tablespoons of sauerkraut to the bottom half of each slider bun. Reserve.

In a medium bowl, add the beef and sausage, mustard, Worcestershire sauce, salt and pepper. Blend together with a fork, mashing to combine. (You can also use your hands) Divide the mixture into 12 equal portions, form the portions into patties a little larger than the diameter of the slider buns.

Heat the skillet over medium-high heat and add half of the patties. (If they will all fit in the skillet without crowding then do so) press a slight indentation in the center of each patty to prevent it from balling up during cooking. Cook the patties for 3 minutes on the first side and 1 to 2 minutes on the other side for medium. Transfer to a plate, add a slice of cheese to each one and cover the plate with foil to keep warm while cooking the remaining patties.

To finish assembling the siders, add a patty on top of the sauerkraut, place the top of the slider bun on and a long cocktail pick to keep it together. Serve immediately.

Serves 12 as appetizers and 6 for main entree