Prepare oven: Preheat the oven to 425°F (220°C). Line a large sheet pan with parchment paper if desired.
Prepare Brussels sprouts: Toss the Brussels sprouts with the olive oil and salt and spread in an even layer on the prepared pan.
Roast: Roast for 15 minutes, then remove the pan from the oven and stir the Brussels sprouts.
Add Kielbasa: Add the sliced kielbasa to the pan, stir to combine, and return to the oven. Roast for an additional 15 minutes, or until the Brussels sprouts are tender and caramelized and the kielbasa is lightly browned.
Cook pasta: Meanwhile, bring a large pot of salted water to a boil. Cook the pasta according to package directions until al dente. Reserve ½ cup of the pasta water, then drain.
Combine pasta: In a large bowl or the pasta pot, combine the cooked pasta, roasted Brussels sprouts, kielbasa, pesto, and ¼ cup of the reserved pasta water. Toss until well coated, adding the remaining pasta water as needed if the pasta seems dry.
Add cheese: Stir in the Parmesan cheese until evenly distributed.
Enjoy: Taste and adjust seasoning if needed. Serve warm with additional Parmesan on top.