Preheat the oven and prepare the pan. Set your oven to 200°C (400°F) and line a large, rimmed baking sheet with baking paper. This high heat is crucial for getting that lovely golden-brown colour on both the chicken skin and the vegetables.

Season the vegetables. In a large bowl, toss the courgette chunks, bell pepper pieces, red onion wedges, and sliced garlic with 1½ tablespoons of olive oil, a generous pinch of salt, and a few grinds of black pepper. Spread them out evenly on the prepared baking sheet, leaving space in the middle for the chicken.

Prepare the chicken. Pat the chicken thighs dry with kitchen paper — this is the secret to crispy skin. In the same bowl, combine the remaining olive oil with the za'atar spice. Rub this mixture all over the chicken thighs, ensuring every bit of skin is coated. You'll smell the fragrant, earthy aroma of the za'atar as you work.

Arrange the chicken. Place the seasoned chicken thighs, skin-side up, in the centre of the baking sheet among the vegetables. Try not to let the chicken pieces touch each other; this ensures the heat circulates properly and the skin crisps evenly. The vegetables should be in a single layer around them.

Roast the chicken and vegetables. Place the tray in the preheated oven and roast for 35-40 minutes. After 20 minutes, the kitchen will be filled with a warm, nutty scent from the za'atar. At the 35-minute mark, check the chicken — the skin should be a deep golden brown and look crisp to the touch. The vegetables should be tender and slightly charred at the edges.

Check for doneness. The most reliable way to know the chicken is cooked is to insert a meat thermometer into the thickest part of a thigh, avoiding the bone. It should read at least 74°C (165°F). If you don't have a thermometer, pierce the thickest part with a knife; the juices should run clear, not pink.

Rest and finish. Remove the tray from the oven. Squeeze the lemon juice evenly over the chicken and vegetables. Let everything rest on the tray for 5-10 minutes. This resting period allows the juices to redistribute throughout the chicken, ensuring every bite is moist. Sprinkle with fresh parsley or mint and toasted sesame seeds if using, then serve straight from the tray or on a large platter.