Question: how to heat up fully cooked kielbasa?
Answer: Roast: Place kielbasa on tray in a 350° oven for about 20 minutes, turning frequently. Sautée: Cut kielbasa into 1” thick slices and pan fry it with oil and sliced onions. Boil: Place kielbasa in pot of water. Bring water to boil, then turn down heat and let simmer for 5 to 10 minutes.