Remove the leaves and core from the cauliflower, then use a sharp knife to cut it into four to six thick, even slices about 1 to 1.5 inches thick.
In a bowl, mix the olive oil, salt, pepper, and smoked paprika. Brush this mixture generously over both sides of each cauliflower steak, ensuring they are well coated.
Heat a large cast-iron skillet over medium-high heat until the oil shimmers and starts to crackle, indicating it's hot enough for searing.
Carefully place the cauliflower steaks into the hot skillet. Let them cook undisturbed for about 4-5 minutes, until the edges are deep golden and crispy, and you hear a satisfying sizzle.
Use a spatula to gently flip each steak, then cook for another 4-5 minutes until the second side is equally golden and crispy, and the cauliflower feels tender when pressed lightly with the spatula.
Remove the steaks from the heat and let them rest for 2 minutes. Squeeze fresh lemon juice over the top to add brightness and balance the smoky sear.
Serve the cauliflower steaks hot, garnished with additional lemon wedges or fresh herbs if desired. Enjoy the crispy, smoky, tender slices with your favorite sides.