Step 1:
Preheat the oven to 400°F. Using a paper towel, thoroughly dry the chicken thighs to ensure crisp skin. Liberally season all sides of the thighs with kosher salt.
Step 2:
Position the chicken thighs skin-side down in a skillet that is medium or large and oven-safe, ensuring the pan is not overcrowded to promote browning. Place the pan over medium heat and allow the thighs to cook without moving them until the skin renders its fat, the meat releases effortlessly from the pan, and the surface achieves a golden-brown hue with darker spots, approximately 15 minutes. Flip the thighs and sear the other side for an additional 5 minutes until browned.
Step 3:
Transfer the chicken to a plate, ensuring the skin faces upward. Return the skillet to medium heat and add the sliced garlic along with ⅓ cup of water. Using a wooden spoon or spatula, deglaze the skillet by scraping up browned bits. Let the water simmer until it nearly evaporates, about 2 minutes. Stir in the coriander and paprika, cooking until their aromas are released, roughly 1 minute. Introduce the blueberries, mustard, honey, and a generous pinch of salt, stirring to combine. Bring the mixture to a gentle simmer and nestle the chicken thighs skin-side up into the sauce.
Step 4:
Move the skillet to the preheated oven. Bake for 15 to 20 minutes, or until the blueberries burst and the chicken is fully cooked through. Once out of the oven, sprinkle with freshly cracked black pepper and drizzle olive oil over the dish. Adjust the seasoning of the sauce with additional salt, pepper, or mustard, if necessary.
Step 5:
Sprinkle the dish with chopped tarragon leaves for a fresh herbal note and serve immediately alongside thick slices of crusty bread to soak up the flavorful sauce.