1
In a small bowl, stir together the oil and smashed garlic. Let sit 10 minutes to infuse garlic flavor into the oil.
2
Brush the oil mixture on both sides of the half breasts. Sprinkle with 1 teaspoon of the salt and ¼ teaspoon of the black pepper.
3
In a large mixing bowl, stir together the melted butter, lemon juice, dried rosemary, remaining ½ teaspoon salt, and remaining ¼ teaspoon black pepper. Add potatoes, carrots, and sprouts to the bowl and toss to coat evenly.
4
Heat oven to 450°F. Place chicken on a large rimmed baking sheet. Bake 10 minutes; reduce heat to 400°F and arrange the potatoes and carrots around the chicken. Return to oven and roast 20 minutes more.
5
Add the Brussels sprouts to the pan, cut-side down, brushing chicken with any remaining butter in the bowl. Bake 20 minutes more or until chicken is no longer pink (180°F in the thigh muscle) and vegetables are tender. Always use a meat thermometer to determine the temperature. Before cutting to serve, let it rest 10 minutes.
