Preheat the oven to 425 degrees F.
Drizzle olive oil over a rimmed baking sheet.
Toss the brats, cabbage, onions and peppers onto the sheet.
Season with salt and pepper. Sprinkle the caraway seeds and garlic powder over everything and shimmy the baking sheet to cover everything with oil.
Carefully add the beer to the baking dish.
Bake for 30-35 minutes until the cabbage is browned and tender.
Strain the liquid.
When cool enough to touch, chop the cabbage roughly.
Meanwhile, arrange rolls on a clean work surface and line with cheese.
Spoon the brats, onions, peppers, and chopped cabbage into the rolls and wrap each tightly in foil.
When ready to grill, preheat the grilled and toss the sandwiches on to heat through and melt the cheese.
Alternatively, bake in the oven at 350 degrees until the sandwiches are heated through and the cheese is melted.
Peel back the foil and devour.
Serve with a thick grainy mustard if desired.