01 - Preheat the oven to 425°F. Line a large baking sheet with parchment paper.
02 - Remove the leaves and stem from the cauliflower, keeping the head intact. Cut into thick spears or wedges, about 1 to 1.5 inches wide.
03 - In a small bowl, combine the olive oil, smoked paprika, cumin, garlic powder, chili powder (if using), salt, and black pepper. Stir until well blended.
04 - Arrange the cauliflower spears on the prepared baking sheet. Brush or drizzle the spice oil mixture evenly over all sides, using your hands or a pastry brush to coat thoroughly.
05 - Roast for 25–30 minutes, turning once halfway through, until the cauliflower is golden brown with crisp edges and tender inside.
06 - Remove from the oven. Immediately drizzle with lemon juice and sprinkle with fresh parsley if desired. Serve hot.