Preheat oven to 425°F (or 415°F on convection roast).

Trim excess fat from the chicken thighs and pat them dry with paper towels. Using kitchen shears or a sharp knife, cut a 2 -inch slit in the center of each chicken skin.

In a small bowl, combine garlic powder, ½ teaspoon Soffritto, ¼ teaspoon salt, and 3 tablespoons oil (it will be a loose marinade).

Spoon the marinade over the chicken, making sure to also get it underneath the skin. Place one sprig of rosemary and 1–2 sprigs of thyme underneath each skin, too. If not using right away, marinate chicken in the refrigerator up to 12 hours.

Break up the head of garlic, separating the cloves and leaving their skin intact. Add them to a roasting pan. Peel the shallots, slice them in half or in quarters depending on their size, and add to the pan.

In the cast-iron skillet, heat 2 tablespoons oil over high heat. When the oil begins to shimmer, add the chicken to the skillet, skin side down. Cook 4 minutes or until the skin turns a deep golden brown. (You may need to work in batches.) Flip and cook 1 more minute, then transfer chicken to the roasting pan, skin side up.

Scatter remaining sprigs of rosemary and thyme over the chicken. Sprinkle with remaining ¼ teaspoon Soffritto. Drizzle with remaining 2–3 tablespoons oil and sprinkle with salt to taste.

Roast chicken for 30 minutes.

Add the cherry tomatoes to the roasting pan and pour balsamic vinegar over the chicken. Baste and return to the oven for another 15 minutes, or until the juices run clear and a thermometer inserted in the chicken reads at least 180°F.

Transfer chicken to a platter and cover with foil.

Turn oven to broil and place the roasting pan under the broiler for 1–2 minutes, until the balsamic vinegar has reduced and the tomatoes have blistered. Pour tomatoes, shallots, garlic, and reduced balsamic vinegar over the chicken and serve.