Place the monkfish in a bowl with the olive oil and a pinch of salt. Squeeze half a lemon over the top and cover the bowl. Set inside the refrigerator to infuse for an hour.

Fire up your Ooni pizza oven, aiming to reach 950°F (500°C) on the stone baking board.

Place the cast iron pan in the oven and preheat for 15 minutes.

Remove the pan from the oven and add the fillets. Using tongs and gloves (the hot oil may spit), carefully push the fillets down until they relax. Use the residual heat from the pan to continue cooking the fish outside the oven, continuing to add pressure with tongs as necessary (roughly 3 minutes).

After 3 minutes, the underside of the fish will be a nice golden brown. Discard any excess liquid released by the fish, flip the fillets and return the pan to the oven to cook for another 3 to 5 minutes (depending on the size of the fillets) until cooked through.

The fish should be tender and juicy. To check, insert a sharp knife into the middle of the fillet (the fillet should feel springy). If the knife is hot to the touch, the fish is cooked through.

Rest the fish for 5 minutes before serving. Serve with a squeeze of lemon, fresh parsley, and freshly ground black pepper and serve.