Pan-Seared Kielbasa with Caramelized Onions and Spicy Mustard Sauce

By Lauren Mitchell, Test Kitchen Director · Reviewed by AislePrompt Editorial · Published 2026-05-22 · Updated 2026-05-22

A hearty Polish-inspired dish featuring pan-seared kielbasa sausage topped with sweet caramelized onions and served with a tangy, spicy mustard sauce. This polish-inspired pork ready in about 40 minutes blends large, thinly sliced yellow onion, olive oil, butter into a versatile sauce that lifts everything from grain bowls and roasted vegetables to grilled proteins — a small-batch staple worth keeping in the fridge. Each serving lands at about 400 calories and feeds 4, so a small batch covers several meals across the week without taking over the fridge. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 1 lb, sliced into 1/2-inch rounds kielbasa sausage
• 2 large, thinly sliced yellow onion
• 3 tbsp olive oil
• 2 tbsp butter
• 2, minced garlic cloves
• 3 tbsp Dijon mustard
• 2 tbsp whole grain mustard
• 1 tbsp honey
• 1 tbsp apple cider vinegar
• 1/2 tsp smoked paprika
• 1/4 tsp black pepper
• 2 tbsp, chopped fresh parsley

Instructions

1. Step 1: Heat 1 tbsp olive oil in a large skillet over medium heat. Add 2 large thinly sliced yellow onions and 2 tbsp butter, cooking for 20 minutes while stirring occasionally until deep golden and caramelized.
2. Step 2: In a separate pan, heat 2 tbsp olive oil over medium-high heat. Add 1 lb sliced kielbasa rounds and sear for 3-4 minutes per side until edges are crispy and browned.
3. Step 3: Add 2 minced garlic cloves to the caramelized onions, cooking for 1 minute until fragrant.
4. Step 4: Stir together 3 tbsp Dijon mustard, 2 tbsp whole grain mustard, 1 tbsp honey, 1 tbsp apple cider vinegar, 1/2 tsp smoked paprika, and 1/4 tsp black pepper in a small bowl to create the spicy mustard sauce.
5. Step 5: Plate the kielbasa, top with caramelized onions, drizzle with the mustard sauce, and sprinkle 2 tbsp chopped fresh parsley over the dish before serving.