Crispy Chicken Thighs with Roasted Brussels Sprouts and Red Onions

Heat oven to 425 °F. On a large rimmed baking sheet, toss the Brussels sprouts, onion, 2 Tbsp oil, 1/2 tsp salt and 1/4 tsp pepper. Roast until golden brown and tender, 20 to 25 minutes. Meanwhile, heat the remaining Tbsp oil in a large skillet over medium heat. Season the chicken with 1/2 tsp each salt and pepper and cook, skin-side down, until the skin is crisp, 7 to 8 minutes. Turn the chicken, add the garlic and rosemary to the pan, and cook until the garlic is golden brown and the chicken is cooked through, 5 to 6 minutes more. Serve with the vegetables.