In a small bowl, combine the kosher salt, black pepper, and garlic powder. Pat the chicken thighs completely dry with paper towels, then season them generously on all sides with the spice mixture.

Heat 1 tbsp of olive oil in a large skillet over medium-high heat. Once the oil is shimmering, carefully place the chicken thighs in the skillet in a single layer. Sear for 5-7 minutes per side, without moving them, until a deep golden-brown crust forms and they are cooked through (an instant-read thermometer should register 165°F or 74°C).

Remove the cooked chicken from the skillet and transfer it to a clean plate. Set aside and keep warm while you make the sauce.

Reduce the heat under the skillet to medium. Add the finely chopped shallot to the remaining chicken drippings in the pan and sauté for 2-3 minutes until softened and translucent.

Add the minced garlic and fresh thyme leaves, stirring constantly for about 30 seconds until fragrant.

Pour the balsamic vinegar into the skillet to deglaze the pan. Use a wooden spoon or whisk to scrape up any delicious browned bits from the bottom. Allow the vinegar to bubble and reduce by about half, which should take 1-2 minutes.

Stir in the chicken broth, honey, and fresh blueberries. Bring the mixture to a steady simmer and cook for 5-6 minutes. As it simmers, gently press some of the blueberries with the back of your spoon to release their juices. The sauce will thicken slightly.

Remove the skillet from the heat. Add the cold, cubed butter and whisk continuously until it has completely melted into the sauce. This will make the sauce rich, smooth, and glossy.

Return the seared chicken thighs and any juices that have collected on the plate back to the skillet. Turn the chicken to coat it completely in the warm blueberry thyme sauce.

Garnish with extra fresh thyme sprigs and serve immediately. This Blueberry Thyme Chicken pairs beautifully with creamy polenta, mashed potatoes, or roasted asparagus.