Step 1: Prepare the Brussels Sprouts: Preheat oven to 400°F (200°C). Toss halved Brussels sprouts with olive oil, salt, pepper, and garlic powder. Spread evenly on a baking sheet, cut side down. Roast for 20–25 minutes, flipping halfway, until golden brown and crispy.
Step 2: Cook the Chicken: While sprouts are roasting, season chicken with salt and pepper. Heat olive oil in a large skillet over medium-high heat. Sear chicken breasts for 5–6 minutes per side until golden and nearly cooked through. Remove and set aside.
Step 3: Make the Balsamic Glaze: In the same skillet, add minced garlic and sauté 1 minute. Stir in balsamic vinegar, honey, and Dijon mustard. Simmer for 3–4 minutes until slightly thickened. Return chicken to skillet, coating with glaze. Simmer until chicken is fully cooked (internal temp 165°F / 74°C).
Step 4: Serve: Plate chicken with roasted Brussels sprouts on the side. Spoon extra glaze over the chicken. Garnish with fresh thyme or parsley if desired.