Preheat your oven to 220°C (430°F), and line a baking sheet with parchment paper for easy cleanup.
Using a sharp serrated knife, carefully slice the cauliflower into about 1-inch thick steaks, starting from the center and working outward. You should get 2-3 main steaks, with some florets falling off to the sides.
Place the cauliflower steaks on the prepared baking sheet, spreading them out evenly. Brush both sides with olive oil using a pastry brush or your fingers, ensuring they are well coated.
Sprinkle the steaks evenly with salt, black pepper, and smoked paprika if using, pressing the spices gently into the surface for better adhesion.
Place the baking sheet in the oven and roast for 10 minutes, allowing the edges to begin caramelizing and turning golden brown.
Use tongs to carefully flip each steak to the other side, then return to the oven to roast for another 10-15 minutes, until the edges are crispy and deeply browned, and the inside is tender when pierced with a fork.
Remove the cauliflower steaks from the oven, and let them rest for 5 minutes on the baking sheet. Meanwhile, zest the lemon directly over the steaks and squeeze fresh lemon juice on top for a bright, tangy finish.
Serve the cauliflower steaks hot, garnished with additional lemon wedges if desired, and enjoy the crispy, smoky, tender interior with a zesty kick.