Some chefs like using kosher chickens because they're salted and you get awesome flavor without brining.
- 2 teaspoons minced garlic plus 1 head of garlic, halved crosswise
- 4 teaspoons kosher salt plus more for seasoning
- 1 teaspoon freshly ground black pepper plus more for seasoning
- 1 teaspoon crushed red pepper flakes
- 4 fennel bulbs (3 pounds), trimmed, each cut into 8 wedges, plus 1/4 cup fronds
- 2 pounds fingerling potatoes, halved lengthwise
- 24 small carrots, peeled or scrubbed
- 8 shallots, halved lengthwise
- 3 lemons, 1 thinly sliced, 2 halved
- 1 orange, cut crosswise into 8 slices
- 8 tablespoons olive oil, divided, plus more
- 2 4-pound kosher chickens
Preheat oven to 450°. Toast fennel seeds in a small dry skillet over medium heat, stirring often, until fragrant and slightly darker, 2–3 minutes. Let cool; finely grind in spice mill. Mix fennel, lemon zest, garlic, 4 tsp. salt, 1 tsp. pepper, and red pepper flakes in a small bowl. Set spice mixture aside.
Place fennel wedges, potatoes, carrots, shallots, and lemon and orange slices in a large heavy roasting pan. Drizzle 4 Tbsp. oil over, season with salt and pepper, and toss well to coat. Spread out in an even layer.
Rub remaining 4 Tbsp. oil all over the chickens. Season chickens inside and out with spice mixture. Stuff each chicken with a lemon half and half head of garlic. Tie legs together loosely with twine.
Set a roasting rack over vegetables in pan; place chickens on rack. Roast until chickens are cooked through and an instant-read thermometer inserted into the thickest part of thighs registers 165°, about 1 hour.
Preheat broiler. Transfer chickens to a carving board and let rest for 15 minutes.
Meanwhile, place roasting pan on stove over 2 burners. Transfer lemon and orange slices to a small bowl. Cook vegetables over medium heat, stirring often, until liquid is evaporated, 8–10 minutes. Set pan under broiler; cook vegetables, rotating pan once, until browned in spots, about 5 minutes.
Season vegetables to taste with salt and pepper. Squeeze juice from remaining lemon halves over vegetables to taste.
Carve chickens. Divide roasted vegetables and chicken among plates. Garnish with reserved citrus slices and fennel fronds.