- Preheat grill.
- In large skillet combine onions and beer; bring to a simmer over medium heat. Add bratwurst and simmer 10 minutes. Transfer bratwurst to plate; blot dry with paper towels.
- Bring onions and beer to a boil; cook 5 to 6 minutes over high heat. Drain onions in colander; discard beer. Melt butter in same skillet. Return onions to melted butter and sauté 6 to8 minutes. Stir in mustard and ketchup.
- While onions are sautéing, brush bratwurst and grill grate with vegetable oil. Place bratwurst on hot grill and cook until casings are crisp and browned, 4 to 6 minutes. To serve, place bratwurst on buns and top with onion mixture.
* Recipes created for given quantity. Changes to quantities are for planning purposes only and have not been tested.