1. If using live crayfish, swiftly and humanely despatch them with a sharp blade to the head or by immersing them in fresh water for 20 minutes. If using frozen, be sure to defrost entirely before cooking. If using tails, have a readymade fish or vegetable stock at hand and proceed from the next step. For the crayfish stock, set a large pot of water over high heat. Once boiling, plunge the crayfish into the pot, along with half the head of celery (leaves included) and an onion or two shallots. Add in a few black peppercorns if desired. Boil the crayfish for 10 minutes for medium size and 15 minutes if large. Once cooked, remove the crayfish from the pot and set aside to cool. Skim any foam or scum from the top of the stock and strain, discarding the peppercorns, celery and onion. Set the stock aside until needed.
2. Once cooled, twist off the crayfish tails and legs, discarding the body carapace. Use a sharp knife to split each tail in half and remove the alimentary canal, rinsing the tail clean under cold water if needs be. Crack open the legs and reserve the meat. Set the tails aside until needed.
3. In a casserole over medium heat, gently cook up the onion or shallots in the butter until they are soft and translucent. Finely chop the remaining celery and with the chopped fennel, add to the onion and sauté until soft and translucent. Add the garlic and fry over high heat for a further minute or two. Stir to combine and season with salt and pepper.
4. Rinse the arborio rice under cold water until it runs clear. Add the rice to the casserole and stir through the vegetables before deglazing the pot with the Cap Classique. Leave to cook for a minute or two before lowering the heat to medium. Pour in the crayfish stock and stir until all the liquid has been absorbed. If the rice is not yet cooked through, add a little water, stirring throughout.
5. To check that your rice is cooked, simply press a grain between your thumb and forefinger – if it has slight give before squashing, then it is ready. Once cooked, stir in the crayfish leg meat and the grated Parmesan cheese. Keep the risotto warm until ready to serve.