Step 1: Preheat and chop: Set the oven to 200°C (400°F) and preheat. Wash and cut all vegetables into even small pieces — uniform size means they finish together. Trim the ugly bits as you go; nicer pieces look better on the plate and are easier for kids to accept.
Step 2: Season and toss: In a large bowl, add the vegetables, drizzle olive oil, and sprinkle garlic powder, oregano, salt, and black pepper. Toss with your hands until every piece wears a thin film of oil.
Step 3: Spread on the sheet pan: Lay the vegetables in a single layer with gaps between them. Crowding makes them steam; a single layer is what roasts on the char. If it does not fit one pan, use two rather than stack — that charred aroma is the soul of this dish.
Step 4: Roast in the oven: Roast at 200°C for 18–22 minutes, flipping once halfway. They are done when the edges are lightly charred and a fork slides through easily.
Step 5: Portion and refrigerate: Cool, then portion into 4–5 containers. They keep 4–5 days in the fridge. Reheat in the microwave or a skillet before eating. Portion by a single meal's amount so grabbing a box is a full serving — no weighing each time, which makes the habit stick.
