Preheat the oven: Set it to 425°F (220°C).
High heat means caramelized edges and deeper flavor.
Prep the pan: Line a large rimmed baking sheet with parchment for easier cleanup. If you have two smaller sheets, use both to avoid crowding.
Cut the veggies: Aim for even pieces so everything cooks at the same pace. Potatoes should be smaller since they take longer.
Mix the seasoning: In a large bowl, combine olive oil, garlic, smoked paprika, Italian seasoning, red pepper flakes (if using), salt, and black pepper.
Toss the vegetables: Add potatoes, peppers, onion, broccoli, and zucchini to the bowl.
Toss until everything is well coated.
Spread on the sheet: Arrange vegetables in a single layer. Keep space between pieces for good browning. If crowded, divide across two pans.
Roast the vegetables: Place in the oven and roast for 12 minutes to give potatoes a head start.
Add the sausage: Pull the pan out, scatter sliced sausage over the top, and return to the oven.
Roast until golden: Cook 15–18 more minutes, stirring once halfway, until the potatoes are tender and the sausage edges are browned.
Finish with brightness: Squeeze fresh lemon over the pan.
Taste and add a pinch more salt or pepper if needed.
Garnish and serve: Sprinkle with chopped parsley or basil. Serve as-is, or over rice, quinoa, or cauliflower rice.