Preheat your oven to 400°F (200°C). Place a large skillet over medium-high heat and add a tablespoon of olive oil, allowing it to warm until shimmering and fragrant.
Season the chicken thighs generously with salt, pepper, and a pinch of cinnamon on both sides. Once the oil is hot, place the chicken thighs skin-side down into the skillet. Sear for about 5-7 minutes until the skin is golden brown and crispy, hearing a satisfying sizzle.
While the chicken is searing, toss the sliced squash and onion rings in a little olive oil, minced garlic, chopped sage, salt, and pepper until evenly coated. Spread the seasoned vegetables around the chicken in the skillet.
Transfer the skillet to the preheated oven and roast uncovered for about 40 minutes. During cooking, the chicken skin will become crispy and the vegetables will caramelize, turning a deep amber color and softening.
Remove the skillet from the oven and check that the chicken is cooked through—juices should run clear when pierced, and the meat should register at least 165°F (74°C). Let rest for a few minutes.
Serve the chicken thighs topped with the roasted vegetables, allowing juices to mingle. The dish showcases crispy skin, tender meat, and caramelized, flavorful vegetables with a warm, autumnal aroma.
