Preheat the oven to 425℉. Line a large rimmed baking sheet with parchment paper.
Place the gnocchi (do not thaw if using frozen gnocchi), peppers, onions, tomatoes, and garlic on the baking sheet. If using dried rosemary and/or basil, add those to the pan now. Drizzle with olive oil and toss to coat.
Spread the vegetables in an even layer on the pan and place the kielbasa on top of the vegetable mixture. If using fresh rosemary, lay sprigs on top of the vegetables.
Place the baking sheet in the oven and bake for 25 minutes, stirring halfway through.
Remove the pan from the oven and top with the spinach (do not stir). Return the pan to the oven and bake for an additional 2 minutes. Remove the pan and stir.
Season with salt and pepper. Sprinkle with basil and shredded parmesan just before serving.
