Remove the outer leaves from each cauliflower head. Cut off the bottom stem end so that you create a flat base and can stand the cauliflower up on a cutting board. Resting the cauliflower on the stem, trim away the sides, then cut the remaining head into 2-3 thick “steaks.”
In a bowl, combine olive oil, lemon juice, garlic, honey, and salt.
Brush each cauliflower steak with the oil mixture and grill on medium heat, 5 minutes on each side. Sprinkle with red pepper flakes and parsley and serve.