Preheat oven to 220°C / 425°F.
Toss potatoes and Brussels sprouts with olive oil, salt and pepper. Roast for 15 min.
Mix Dijon, maple syrup, garlic and half the thyme leaves. Coat the chicken thighs.
Add the chicken and roast for 20-25 min. Broil for 2 min for a sticky glaze, then top with fresh thyme.
