01 - Set oven to 425°F. Line a baking sheet with parchment paper for easy cleanup.
02 - Remove outer leaves from each cauliflower and carefully trim stem, leaving the core intact. Stand upright and cut into 3/4-inch-thick slices to form steaks. Reserve any loose florets for another use.
03 - In a small bowl, whisk olive oil with smoked paprika, cumin, garlic powder, onion powder, salt, black pepper, and chili flakes.
04 - Arrange cauliflower steaks on the prepared baking sheet. Use a pastry brush or spoon to thoroughly coat both sides with marinade.
05 - Roast steaks for 15 minutes. Carefully flip each piece with a spatula, then roast for 12 to 15 minutes more, until tender and golden brown.
06 - Transfer roasted steaks to plates. Sprinkle with chopped parsley and serve with lemon wedges.