In a large mixing bowl, combine the Greek yogurt, 4 tablespoons of olive oil, minced garlic, lemon zest, lemon juice, ½ teaspoon of kosher salt, ¼ teaspoon of black pepper, 1 teaspoon of Greek seasoning, ½ teaspoon of ground fennel, and honey. Whisk until well combined.
Add the chicken breasts to the marinade, making sure they are fully coated. Cover the bowl and let the chicken marinate in the refrigerator for at least 30 minutes (or up to overnight for more flavor).
While the chicken marinates, slice the cauliflower into even florets. In a separate bowl, toss the cauliflower with the remaining 2 tablespoons of olive oil, ½ teaspoon of kosher salt, ¼ teaspoon of black pepper, 1 teaspoon of Greek seasoning, and ½ teaspoon of ground fennel.
Preheat your oven to 400°F (200°C).
Line your sheet pan with parchment paper. Place the marinated chicken breasts in the center of the pan and surround them with the seasoned cauliflower florets. If using, scatter the halved cherry or Glory tomatoes around the pan.
Roast in the preheated oven for 25-30 minutes, or until the chicken is cooked through (internal temperature should reach 165°F) and the cauliflower is tender and slightly charred.
Remove from the oven and sprinkle the dish with freshly chopped parsley. Serve warm, and enjoy!
