Set up the grill for indirect heat at 350 degrees and add two bottles of beer to a cast iron skillet. Bring it to a boil. Note: Try to avoid highly flavored beers and keep with a standard IPA, Wheat, or Blonde.
Add beer brats to the skillet and cook the brats in the beer until they are cooked through (about 20 minutes).
Remove the skillet and set up the grill for direct heat. Remove the brats from the beer and place directly on the grill grating to get a nice sear. It took about three minutes on each side.
Honey Mustard Sauce
While the beer brats are on the grill, combine beer, brown sugar and mustards in a pot over medium high heat. Bring to a boil. Lower heat to a simmer and allow to simmer for 10-15 minutes. Whisk the contents well to keep smooth.
After 10-15 minutes, whisk together the cornstarch and water together and pour into beer/mustard mixture. Bring it back to a boil and cook for about 1 minute. Stir constantly and sauce will thicken.
Add sliced beer brats to the beer/mustard mixture and combine.