One 3 ½- to 4-pound chicken
2 Tbsp. kosher salt
1 Tbsp. ground pepper
1 Tbsp. caraway seeds
2 tsp. fennel seeds
1 tsp. coriander seeds
¼ cup (½ stick) unsalted butter, melted
2 garlic cloves, minced
1 Tbsp. chopped fresh thyme, plus more for garnish
1 lemon, cut into quarters
1 yellow onion, peeled and cut into quarters (leave the root end attached)
1 fennel bulb, trimmed and cut into quarters

1. Preheat oven to 425°F. Pat the chicken dry with paper towels. Season all over with the salt and pepper. Let it sit at room temperature while you prepare the spice mix.

2. Heat the caraway, fennel and coriander seeds in a dry skillet over medium heat. Toast until the spices begin to brown and smell fragrant, 1 to 2 minutes. Transfer to a spice grinder or mortar and pestle. Coarsely grind. Transfer spices to a small bowl.

3. Add the butter, garlic and thyme to the bowl with spices. Stir together to form a paste.

4. Generously brush the butter mixture all over the chicken. Place the chicken, breast side up, in a 9-by-13-inch roasting pan. Tuck the wings under the chicken. Place a lemon quarter inside the cavity and tie the legs together with kitchen twine, if desired.

5. Scatter the onion, fennel bulb and remaining lemons around the chicken. Roast until the skin begins to brown, about 40 minutes.

6. Reduce oven temperature to 375°F. Stir the onions, fennel and lemons in the pan. Roast until the chicken is golden brown and the internal temperature reads 160°F on an instant-read thermometer when inserted into the thickest part of the thigh, 35 to 45 minutes more. Let rest for 10 minutes before carving. Carve into pieces. Serve with the lemon, onion, fennel and additional fresh thyme.