01 - Preheat your grill to medium-high heat, approximately 400°F.
02 - Heat vegetable oil in a skillet over medium heat. Add sliced onions and cook, stirring frequently, until softened and golden, about 8 minutes. Add drained sauerkraut and caraway seeds if using. Stir and cook for an additional 3–4 minutes until heated through. Season with black pepper to taste.
03 - Place beef bratwursts on the preheated grill. Turn occasionally and grill for 12–15 minutes until evenly browned and fully cooked. Internal temperature should reach 160°F for safe consumption.
04 - During the final 2 minutes of grilling, place buns cut-side down on the grill to toast lightly until golden brown.
05 - Place a grilled bratwurst in each toasted bun. Top generously with warm sauerkraut-onion mixture. Add mustard, ketchup, and chopped pickles as desired. Serve immediately while hot.