Preheat oven to 400°F. Line a very large sheet pan with parchment paper or foil and set aside.
Peel and thinly slice the carrots (⅛ inch thick). Wash and chop red potatoes (leave peel on). Cut into small pieces.
Halve the zucchini lengthwise and cut thick half-moons about ½ inch thick. Coarsely chop broccoli into florets. Trim and halve the Brussels sprouts. Chop sausage into thick (½-inch) coins.
Place all veggies and sausage on the prepared sheet pan. Drizzle the olive oil over everything. Add the seasonings: basil, oregano, parsley, garlic powder, onion powder, thyme, and optional red pepper flakes. Season with salt and pepper. Toss to coat all the veggies and sausage in the seasoning/oil mixture.
Space veggies/sausage so none overlap and everything has plenty of space to roast.
Place sheet pan in the oven and roast for 15 minutes. Remove and toss/flip the veggies and sausage. Return to oven for another 10–20 minutes or until veggies are crisp-tender.
Remove pan from oven and top with freshly grated Parmesan and fresh chopped parsley if desired.
Serve as is out of the oven or on top of rice, quinoa, or cooked cauliflower rice.
