Remove the smoked sausage from packaging. If links are long, cut each into 3–4 pieces (about 3–4 inches) or leave whole depending on serving preference. If you prefer cross-sections, slice into 1/2-inch rounds.

Heat pan

Place a large skillet or cast-iron pan over medium heat and let it warm for 1–2 minutes until evenly hot.

Brown sausage

Add the sausage pieces (no oil required if they are fatty; if very lean, add 1 tsp oil) in a single layer. Cook without moving for 2–3 minutes to develop a brown crust, then flip or stir and brown the other sides for another 2–3 minutes. Total browning time about 6–8 minutes for whole links, or 4–6 minutes for sliced rounds. Sausage is pre-cooked; you are aiming for color and heat-through.

For Pan Glaze (optional)

Make glaze

After browning the sausage, push the pieces to one side of the pan. Lower heat to medium-low. Add 1 tbsp oil and 1 tbsp butter to the clear side of the pan and let butter melt, about 30 seconds. Stir in 1 tbsp brown sugar, 1 tsp Dijon mustard, 1 tsp apple cider vinegar, 1 tsp black pepper and 1/4 tsp red pepper flakes until the brown sugar dissolves and the mixture is cohesive, about 30–60 seconds.

Coat sausage

Toss the browned sausage through the glaze so each piece is coated. Cook together for 1–2 minutes to allow the glaze to thicken slightly and cling to the sausage. Taste and adjust seasoning (add a pinch of salt if desired).

To Serve (optional)

Sauté vegetables (optional)

If using onions and peppers, after browning sausage remove it to a plate and set aside. Add the sliced onion and bell pepper to the hot pan with 1 tsp oil. Sauté over medium heat for 6–8 minutes, stirring occasionally, until softened and slightly caramelized. Return sausage to the pan with vegetables and toss with glaze or pan juices for 1–2 minutes to combine.

Assemble

Warm buns briefly in the oven or on the skillet, then fill with glazed sausage (and vegetables if used). Add mustard or ketchup to taste. Alternatively, serve sausage whole or sliced on a platter with sides such as sauerkraut, potato salad, or roasted vegetables.