Preheat your outdoor grill to medium-high heat (around 400-425°F) and lightly oil the grate to prevent sticking.

Remove the outer leaves from the cauliflower head. Place it stem-side down on a cutting board and, using a sharp chef's knife, cut straight down through the center of the head to create two halves.

From each half, cut 1 to 1.5-inch thick 'steaks' parallel to the first cut. You should get about 3-4 steaks from a large head. (Save any florets that fall off for roasting or another use!)

In a small bowl, whisk together the olive oil, BBQ seasoning, smoked paprika, minced garlic, onion powder, cayenne (if using), lemon zest, 1 tablespoon lemon juice, salt, and pepper.

Generously brush both sides of each cauliflower steak with the BBQ mixture, making sure to get into all the nooks and crannies.

Place the cauliflower steaks on the preheated grill and cook for 5-6 minutes per side, or until tender with visible grill marks and caramelized edges. Be careful when flipping as they can be fragile.

Transfer the grilled cauliflower steaks to a serving platter, drizzle with remaining lemon juice, and sprinkle with fresh parsley.