1Preheat the oven on the 750°F setting while making the sauce (preheat can take up to 20 minutes).
2To make the lemon-herb sauce, pulse the parsley, dill, garlic, eschallot, capers, lemon zest and juice, salt and pepper in a food processor until finely chopped.
3With the motor running, slowly add the oil. Process for 45 seconds until well combined, pausing, if necessary, to scrape the sides. Transfer the sauce to a small bowl, cover and reserve.
4For the cauliflower steaks, trim the base and the rounded sides from the cauliflower, leaving the core intact. Using a large knife, cut the cauliflower from top to base into three 1-inch-thick steaks. Brush both sides of each steak with half the oil and season with salt and pepper. (Reserve any cauliflower trimmings for another use)
5Using the removable handle, place the pizza pan in the oven to heat for 2 minutes. Remove the pan and drizzle the remaining oil over the base.
6Carefully place the cauliflower steaks in the hot pan and return to the oven using the removable handle. Cook for 3 minutes.
7Using the removable handle, remove the pan from the oven, carefully turn the cauliflower over, then return to the oven and cook for a further 2-3 minutes until browned and tender.
8Using the removable handle, transfer the pan to a heatproof surface. Spoon the lemon-herb sauce over the cauliflower to serve.