Make Balsamic Chicken with Roasted Vegetables tonight: roast marinated chicken and veggies for a sticky, caramelized dinner.
Preheat the oven to 425°F so it's ready when everything is assembled. While it warms, pat the boneless skinless chicken thighs dry, trim any remaining fat, and season them evenly with kosher salt and freshly cracked black pepper; set them on a small plate to rest. Lightly spray two large rimmed baking sheets with cooking spray and set them aside on the painted pine wood surface so they're ready for an even, single-layer roast.
In a small glass jar combine 1/4 cup plus 1 tablespoon balsamic vinegar, 2 tablespoons extra virgin olive oil, smashed chopped garlic, 1/2 teaspoon sugar (optional), chopped fresh rosemary, dried oregano or thyme, and the chopped sage leaves; seal or rest the jar lid beside it. Place the olive oil in a small clear bottle and the balsamic in a compact glass jar, and keep kosher salt and fresh black pepper in two tiny ceramic bowls—everything visible as discrete vessels. Toss the prepared vegetables briefly in a shallow bowl if you like, but do not mix them with the chicken yet.
In a large matte grey ceramic mixing bowl gently pour the balsamic-olive oil mixture over the chicken and vegetables and use your hands to toss everything until the pieces are evenly coated and glossy—chicken pieces slick with marinade, vegetables shimmering with oil and herb flecks. Transfer and arrange the chicken and vegetables onto the two prepared rimmed rectangular baking sheets in a strict single layer, keeping vegetables from touching the chicken so they roast rather than steam; scatter any extra rosemary and sage across the sheets. The scene now shows two rectangular, oiled baking sheets with raw, marinated chicken and separated colorful vegetables: bright red pepper strips, halved asparagus, mushroom slices, chunky red onion, and long carrot segments all visibly coated and ready to roast.

Slide the prepared sheets into the preheated oven (not visible here) and roast until the chicken is cooked through and the vegetables are tender and caramelized at the edges, about 20–25 minutes while rotating sheets top to bottom midway. Once out of the oven, transfer the golden, slightly glossy, balsamic-glazed chicken and the deeply caramelized vegetables onto a rectangular white stoneware serving platter, garnishing with a few fresh rosemary sprigs and a final drizzle of the reserved balsamic if desired. Serve immediately while the chicken retains a warm, sticky sheen and the vegetables show charred, sweet edges.
