This chicken has a triple hit of fennel: fennel seeds in the marinade, fennel pollen in the vinaigrette and grilled fennel on the side.
Season the chicken breasts and thighs with salt and pepper. In a large bowl, combine 2 tablespoons of the olive oil with the fennel seeds and 1 tablespoon of the crushed red pepper. Add the chicken pieces and turn to coat well with the marinade.
Bring a large saucepan of salted water to a boil. Add the fennel slices and blanch over moderately high heat for 2 minutes. With a slotted spoon, transfer the fennel to paper towels to drain. Add the onion wedges to the boiling water and blanch for 1 minute; drain well. Brush the fennel, onion and tomatoes with olive oil and season with salt and pepper.
Light a grill. Grill the fennel slices and onions over moderately high heat until lightly charred and tender, about 3 minutes per side. Transfer to a platter and cover loosely with foil. Grill the tomatoes cut sides down until lightly charred, about 2 minutes per side; add to the platter.
In a small bowl, combine the remaining 1/2 cup of olive oil and 1/2 teaspoon of crushed red pepper with the garlic, lemon zest, lemon juice and fennel pollen and season the dressing with salt and pepper.
Remove the chicken from the marinade. Grill the chicken skin side down over moderately high heat, basting once with 2 tablespoons of the lemon dressing, until charred, about 12 minutes. Turn the chicken and grill until cooked through, about 8 minutes longer for the breasts and 12 minutes longer for the thighs.
Arrange the grilled chicken on the platter with the grilled vegetables. Spoon the remaining lemon dressing over the chicken and vegetables, garnish with the fennel fronds and serve.
The blanched vegetables and lemon dressing can be refrigerated overnight. Bring them to room temperature before proceeding.
Italy’s Alto Adige region is known for its high-acid, aromatic grapes, such as Müller Thurgau. These produce wines that are very fragrant and minerally, perfect complements to the fennel in this dish.