Preheat your oven to 425°F (220°C). A hot oven is crucial for achieving that desirable caramelization on the cauliflower.
Remove the outer leaves from the cauliflower heads and trim the stem, ensuring that the heads are stable. Place each cauliflower head upright on the cutting board.
Using a sharp knife, carefully slice each cauliflower head into 1-inch thick steaks. Aim for at least three to four steaks per head, but keep in mind that the outer florets may fall apart, which can still be roasted alongside the steaks.
Arrange the cauliflower steaks on a baking sheet lined with parchment paper. Lightly spray both sides of each steak with olive oil spray. In a small bowl, mix together the kosher salt, black pepper, garlic powder, smoked paprika, and ground coriander. Sprinkle this seasoning mix evenly over both sides of the cauliflower steaks.
Place the baking sheet in the preheated oven and roast for 20-25 minutes, flipping the steaks halfway through. The cauliflower should be golden brown and tender when done.
Once roasted, remove the cauliflower steaks from the oven and let them cool for a minute. Serve warm as a main dish or side, garnished with your favorite sauces or fresh herbs if desired.
