Place a sheet pan in the oven as it pre-heats to 425°F.
Cut up bell pepper and onion into chunks; place in a medium bowl.
Toss the vegetables with a splash of olive oil, salt and pepper; set aside.
Once oven has reached desired heat level, remove sheet pan from oven and lay vegetables in a single layer.
Return pan to oven and roast for 20 to 25 minutes.
Meanwhile, cut the kielbasa into thin slices, stopping short of cutting all the way through the meat; cutting on chop sticks helps to ensure you don’t cut all the way through.
In a small bowl thoroughly combine the mustard and apricot preserves; set aside.
Once vegetables are roasted, remove them from the oven, give them a stir and place the kielbasa on top.
Return the sheet pan to the oven and allow everything to roast into crisp softness for approximately 30 minutes; basting heavily two or three times with the mustard and preserves mixture.
When done, place under the broiler for just a few minutes.
Remove from oven and serve.
