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A close-up shot of a delicious Grilled Kielbasa Sandwich with Sweet Onion, featuring melted cheese and golden toasted bread.
Daniel

Grilled Kielbasa Sandwiches with Caramelized Sweet Onions

Savor the smoky flavor of grilled kielbasa perfectly paired with tender, sweet caramelized onions and a hint of tangy mustard, all nestled in a toasted bun for an easy and satisfying meal.
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Prep Time 15 minutes
Cook Time 25 minutes
Total Time 40 minutes
Servings: 4 sandwiches
Course: Main Course
Cuisine: American, Polish-inspired
Calories: 650
Ingredients Equipment Method Notes

Ingredients
  

For the Caramelized Sweet Onions
  • 1 large sweet onion e.g., Vidalia or Walla Walla, sliced thinly
  • 2 tbsp olive oil
  • 1 tbsp brown sugar packed
  • 1/2 tsp salt
  • 1/4 tsp black pepper freshly ground
  • 1 tbsp balsamic vinegar
For the Kielbasa and Buns
  • 1.5 lbs smoked kielbasa sausage whole links, pre-cooked
  • 4 hoagie rolls or sturdy hot dog buns
  • 2 tbsp butter melted
For Serving (Optional)
  • 1/4 cup Dijon mustard or yellow mustard, to taste
  • Pickle spears for serving

Equipment

  • Outdoor grill (gas or charcoal)
  • Large skillet or cast-iron pan (grill-safe)
  • Tongs
  • Cutting board
  • Sharp knife
  • Small Bowl
  • Spatula

Method
 

Prepare the Caramelized Onions
  1. Heat the olive oil in a large, grill-safe skillet or cast-iron pan over medium-low heat on your grill or stovetop. Add the thinly sliced sweet onion.
  2. Cook, stirring occasionally, for 10-15 minutes until the onions soften significantly and begin to turn translucent.
  3. Stir in the brown sugar, salt, and black pepper. Continue cooking for another 10-15 minutes, stirring more frequently, until the onions are deeply golden brown and beautifully caramelized.
  4. Stir in the balsamic vinegar and cook for 1-2 minutes more, scraping up any browned bits from the bottom of the pan. Remove from heat and set aside.
Grill the Kielbasa and Buns
  1. Preheat your grill to medium heat (about 350-400°F or 175-200°C).
  2. Score the kielbasa links with a few diagonal slits (about 1/4 inch deep) on both sides. This helps them cook evenly and prevents bursting.
  3. Place the scored kielbasa on the preheated grill grates. Grill for 8-12 minutes, turning occasionally, until heated through and nicely charred on all sides.
  4. While the kielbasa is grilling, brush the inside of the hoagie rolls or buns generously with the melted butter.
  5. During the last 2-3 minutes of kielbasa grilling, place the buttered buns, cut-side down, on the grill grates. Toast lightly until golden brown. Watch them carefully to prevent burning.
Assemble the Sandwiches
  1. Remove the grilled kielbasa and toasted buns from the grill.
  2. Spread a thin layer of Dijon mustard inside each toasted bun.
  3. Place one grilled kielbasa link into each prepared bun.
  4. Top generously with the caramelized sweet onions. Serve immediately, optionally with pickle spears on the side.

Notes

For an extra kick, consider adding a pinch of red pepper flakes to the onions while they caramelize. Leftover caramelized onions can be stored in an airtight container in the refrigerator for up to 3 days. Kielbasa can also be cooked indoors in a skillet if grilling is not an option; just ensure good ventilation.