Heat up grill to 350-375° over direct heat on a grill grate (you want those gorgeous grill marks) and prep the kielbasa.
Make ⅛" cross hatch marks on the kielbasa.
Cut the onions in half and brush with olive oil.
Brush or spray the sweet peppers and Roma tomatoes with olive oil.
When the grill is heated up, place the kielbasa and onions on the grill. Turn them over after five minutes.
Add the sweet peppers and then add the Roma tomatoes when there is 3-4 minutes left. You are looking to char the sweet peppers and cherry tomatoes is all.
Remove everything after the kielbasa is at 145-155° and the vegetables are nicely seared.
Serve everything on a platter.
Storage: Keep leftovers in the refrigerator with the vegetables in an airtight container for three to five days. You can use a freezer-quality plastic bag if you prefer. Reheat in a skillet or microwave.Freezer Friendly: Freeze the leftovers for up to six months in an airtight container. We add the leftovers and vegetables to Tupperware containers with a bit of rice and freeze them for lunches.No Boiling: Purchase and use pre-cooked, smoked kielbasa for this recipe. It's basically reheating the meat with the added flavor from the grill. If you purchase raw kielbasa you will want to cook it differently. Internal Temperature: Shoot for an internal temperature between 145º and 155ºF and check the temperature using an internal temperature probe.Cross Hatching: Crosshatch scoring helps it cook faster, and crisp up nicely on the outside. Don't skip this step.Spray or Oil Grill Grate: Always make sure to oil the grate before use to avoid sticking.