Trim the leaves and cut the cauliflower's core to create a flat base, then carefully slice into 1.5-inch thick steaks, aiming for 3-4 slices per head.
Place the steaks on a clean kitchen towel and sprinkle generously with sea salt, letting them sit for about 10 minutes to draw out excess moisture. This helps achieve a crisp crust.
Pat the salted steaks dry with paper towels to remove surface moisture, which is key for crispiness.
Using a brush or your hands, coat both sides of each steak with olive oil, then season with a little more salt and freshly cracked black pepper for flavor.
Heat a large skillet over medium-high heat until hot and shimmering, around 200°C (390°F). The pan should be hot enough to sizzle when the cauliflower touches it.
Carefully place the cauliflower steaks in the hot pan, pressing gently to ensure contact. Cook for about 4-5 minutes until the bottom develops a deep golden crust and crispy edges.
Flip the steaks carefully with tongs or a spatula, then cook the other side for another 4-5 minutes until similarly golden and tender when pierced with a knife.
Check the doneness by inserting a knife into the center of a steak; it should slide in easily, and the crust should be crispy and deep golden.
Remove the steaks from the pan and place them on a plate. Squeeze fresh lemon juice over the top for brightness and sprinkle with flaky sea salt to finish.
Serve immediately while hot, with extra lemon wedges on the side if desired. Enjoy the smoky, crispy exterior with the tender interior.