01 - Set oven to 425°F (218°C) to ensure high roasting temperature.
02 - Slice bell peppers and onion into even strips for uniform cooking.
03 - Place sausage segments, pepper strips, and onion slices on a large sheet pan. Drizzle with olive oil, sprinkle with dried oregano, salt, and black pepper. Thoroughly toss to coat.
04 - Spread all ingredients into a single layer, avoiding overlap for best caramelization.
05 - Transfer pan to oven and roast for 25-30 minutes, turning contents halfway through for even browning. Sausage should be fully cooked and vegetables tender.
06 - Remove from oven and carefully transfer sausage and peppers to a serving platter. Serve hot.