Slice the fennel bulb into wedges. Trim off the long green stems from the fennel bulbs as well as the very bottom root. Slice each white bulb in half lengthwise from the stem to the root. Place each half cut side-down on your cutting board, then slice lengthwise into 1/2-inch-thick wedges.

Make a bed for the chicken. Add the fennel wedges and grapes to a 9×13-inch baking dish. Toss with half the olive oil, 1/4 of the salt, and a few grinds of black pepper.

Season the chicken: Add the chicken to a large bowl, along with the remaining olive oil, salt, garlic, thyme, and a good grind of black pepper. Use your hands to coat the chicken with the aromatics, pushing them under the skin.

Bake: Nestle the chicken, skin side up, among the fennel and grapes. Pour in the white wine and chicken stock along the sides, avoiding moistening the chicken skin. Bake for 40 minutes, or until the internal temperature reaches 175°F. If desired, during the last two minutes of cooking, turn your oven to broil to crisp up the skin.

Serve: Serve immediately, spooning the juices over the chicken.