Steam the Cod: In a steamer, add water, Sicilian lemon, and thyme. Cook the cod until it starts to flake. After cooking, shred it roughly and squeeze out all the water using a dish towel.
Prepare the Potatoes: Wrap the potatoes in aluminum foil and bake in an oven preheated to 220ºC for approximately 40 minutes or until soft. While still hot, peel and mash them well with a fork.
Mix Cod and Potatoes: Combine the shredded cod with the mashed potatoes and add a tablespoon of cornstarch.
Season the Mixture: Line the bottom of a frying pan with good olive oil over very low heat. Sauté onion, garlic, and some thyme. Use this flavored olive oil to season the cod and potato mixture. Season with salt, black pepper, Sicilian lemon zest, and plenty of parsley.
Fry the Fritters: Shape the mixture with the help of a spoon and fry in oil preheated to 180ºC until golden and crispy. Serve with a little lemon and pepper.