Heat the oven to 425°F. A hotter oven gives better caramelization and crisp edges.

Line a large rimmed sheet pan with parchment for easy cleanup, or use a light coat of oil.

Peel the butternut squash, scoop the seeds, and cut into one-inch cubes. Aim for uniform size so everything cooks evenly. If using delicata, slice into half moons and scoop out seeds. No peeling needed.

Season the squash and onion. Toss the squash and onion wedges with two tablespoons olive oil, half teaspoon salt, and a few grinds of pepper. Spread over the sheet pan in a single layer, leaving gaps for the chicken.

In a small bowl, whisk maple syrup, Dijon, remaining one tablespoon olive oil, cider vinegar, garlic, rosemary, smoked paprika, and red pepper flakes if using. Taste and adjust for your preference. More maple for sweet, more Dijon for tang.

Season the chicken. Sprinkle both sides with half teaspoon salt and several grinds of pepper. Dry chicken browns better.

Coat the chicken. Spoon half of the maple Dijon glaze over the chicken and rub to coat. Reserve the rest for later.

Arrange on the pan. Nestle the chicken pieces among the squash and onion, skin side up if using skin on thighs. Make sure nothing is crowded. Air flow is flavor.

Roast for 20 minutes.

After 20 minutes, remove the pan and brush the remaining glaze over the chicken and a little over the squash. Rotate the pan and return to the oven.

Finish roasting for 10 to 15 more minutes, until the chicken registers 165°F in the thickest part and the squash is tender with caramelized edges. Total time is about 30 to 35 minutes depending on your oven and the size of the chicken pieces.

Optional: If you want extra color, broil for 1 to 2 minutes, watching closely.

Let the chicken rest for 5 minutes. Toss the squash on the pan so it gets glossed with sticky pan juices.

Serve. Spoon everything onto warm plates. Drizzle any remaining pan sauce over the top. Sprinkle with a little chopped rosemary or flat leaf parsley if you like a fresh finish.