For the Yogurt-Honey marinade/sauce: place yogurt, 4 tablespoons oil, garlic, lemon zest, lemon juice, 1 teaspoon salt, ¼ teaspoon pepper, 2 teaspoons Greek seasoning, 2 teaspoons fennel, honey and 1 tablespoon parsley in a medium bow. Whisk until well blended.
Place the chicken breasts in a large zipper-style plastic bag and add half of the Yogurt-Honey marinade/sauce. Close the bag, squeezing out most of the air. Squish the marinade all around the chicken, and refrigerate it 1-12 hours.
Refrigerate the remaining ½ Yogurt-Honey sauce in an airtight container.
The cauliflower can be prepared at this time or right before roasting. Cut the cauliflower as you like it, but keep the pieces no more than 1/2 –inch thick. Place chopped cauliflower in a bowl and add 2 tablespoons oil, ¼ teaspoon kosher salt, ¼ teaspoon black pepper and ¼ teaspoon ground fennel. Mix gently and thoroughly to coat the cauliflower with the oil/seasonings; refrigerate until ready to cook.
When ready to cook, cover a large baking sheet with aluminum foil and spray the foil with nonstick spray. Cut a piece of parchment paper slightly large enough to cover and hang over the chicken; set aside.
Heat oven to 350°F.
Remove the chicken, Yogurt-Honey Sauce and cauliflower from the fridge.
Place the chicken on one end of the baking sheet. Spray one side of the parchment paper and place it (sprayed side down) over the chicken breasts – tucking the parchment around the chicken.
Place the cauliflower, in a single layer, on the other side of the baking sheet. Use up all the remaining space – it’s best not to crowd the cauliflower too much.
Bake at 350°F for 20-30 minutes or until the internal temperature of the breasts registers 155°F.
Remove the parchment paper and set oven to broil.
If adding tomatoes, place them over/around the cauliflower at this time.
Broil the food just long enough (about 2-4 minutes) to give the chicken a little color and add some caramelization to the cauliflower.
Once the internal temperature of the chicken registers 162-165°F, remove the chicken from the oven and cover loosely with foil. If the cauliflower still needs a little color, leave it under the broiler until it’s like you like it.
Transfer the sheet pan to a cooling rack and let rest 2-3 minutes.
Garnish with chopped fresh parsley and serve with extra Yogurt-Honey sauce.