Instructions

1. Gather the ingredients. Position a rack in the center of the oven and heat to 375 F. Line a large sheet pan or roasting pan with foil.
2. Cut 1 medium acorn squash, washed and patted dry in half through the stem end. Scrape out the seeds and strings and discard.
3. Place the squash cut-side down on the cutting board and slice crosswise into 1/2-inch thick half moon-shaped pieces.
4. Rub the squash and 12 large whole garlic cloves, peels left on, all over with the olive oil and place them in a single layer in the prepared roasting pan. Season with 1/2 teaspoon of the fine salt and a few grinds of black pepper. Arrange 1 medium red onion, peeled and cut into 1/2-inch wedges through the root end on top of the squash.
5. Roast the vegetables until softened around the edges, 10 minutes.
6. While the vegetables are roasting, prepare the chicken. Mash together 2 tablespoons salted butter, at room temperature, 1 tablespoon finely chopped fresh rosemary leaves, and 2 tablespoons of the maple syrup with a fork in a small bowl. Don’t worry if the butter and syrup don’t completely emulsify.
7. Carefully slide the butter mixture under the skin of 4 large bone-in, skin-on chicken thighs, pressing gently to spread the butter out on the meat. Season the chicken on both sides with the remaining 1/2 teaspoon fine salt and a few grinds of black pepper.
8. Arrange the chicken pieces skin side-up on top of the vegetables. Drizzle with the remaining 2 tablespoons of maple syrup.
9. Bake, basting once or twice with juices in the bottom of the pan, until an instant-read thermometer inserted into the largest thigh registers 170 F, or the juices run clear when pierced with a knife, about 40 minutes.
10. For extra-crispy skin, switch on the broiler and broil the chicken until it is well browned, 3 to 4 minutes. Serve the chicken immediately with the pan juices drizzled over the top of the chicken and vegetables.