Foryoueats: Root Beer Brats

2 tablespoons butter

1 red onion, sliced into thick rings

2 bottles (32 ounces) root beer

3 tablespoons cornstarch

¼ cup dijon mustard

¼ cup ketchup

1 tablespoon apple cider vinegar

1 tablespoon packed brown sugar

⅛ teaspoon garlic powder

⅛ teaspoon kosher salt

⅛ teaspoon pepper

¼ teaspoon hot sauce

12 brats

12 brat buns

ketchup, for topping

mustard, for topping

Root Beer Brats