Directions. In a large skillet, saute onions in oil until tender. Add the garlic, pepper flakes and pepper; cook 1 minute longer. Stir in the tomatoes, brown sugar, vinegar, hot pepper sauce, Worcestershire and cumin. The next day, preheat the oven to 300°. Rinse the sauerkraut in cold water and squeeze dry. Set a large roasting pan over 2 burners on high heat and melt the duck fat. If you want to smother your brats with barbeque sauce, mustard, and sauerkraut to kill the taste, this recipe is o.k. I'm 100% German, eat brats once a week - but I like the natural flavor of fresh brats. It's actually the poking of the brats with a fork that wrecks this recipe. It dries out the brats and lets the natural flavors seep out. Ingredients. 1 package (16.9 ounces) frozen potato and onion pierogi; 2 tablespoons butter, divided; 2 tablespoons canola oil, divided; 1 package (14 ounces) smoked turkey sausage, cut in half lengthwise and sliced into 1/2-inch pieces