1.In A Slow Cooker, Combine The Bratwurst Links, Butter, Beer, Onions, Cayenne Pepper, Garlic Powder, Garlic And Brown Sugar. Cover And Set To High. Cook For 4 Hours, Stirring Once Per Hour. Add Sauerkraut And Continue Cooking For Another Hour. 2.Serve Bratwurst On Buns With Onions And Top With Your Favorite Condiments.