Mix all the ingredients and let it rest in the fridge overnight.
For the fritters
1. Rinse
Rinse codfish with running water until all the superficial salt has been washed away. Shred codfish into small pieces and soak overnight in a gallon of water.
2. Sieve
Sieve to get rid of the water. Taste it to make sure it isn't still salty (if it is it need to be soaked in clean water for another two hours).
3. Shred the codfish
Using two forks (or your very pretty hands) shred the codfish very finely.
4. Peel potatoes
Peel and grate the potatoes using the coarsest side of the grater. Grate onion on the same side.
5. Mix
Mix potato and codfish. Mix in onion, cilantro, salt, pepper and egg.
6. Fry
Heat half the oil over medium-low heat in a large non-stick frying pan.Fry the codfish and potato mixture by forming small patties with two tablespoons of the patties, never more than 3 at a time. Once brown on the bottom side, flip carefully and cook until golden brown all over.When you've gone through half of the mixture, add the remaining oil to the pan and heat again. Continue with the process until there is no more mixture.
7. Serve
Place on a plate covered with a paper towel to absorb excess oil.Serve on lettuce alongside the yogurt dressing.