Hi, @Mayapapaya! I love your name! 
Not sure how the egg is used in your recipe, but you could try these vegan alternatives, perhaps:
Or, for the equivalent of 1 real egg, add 1 Tablespoon of ground flax seed [sementes de linhaça moída] mixed with 2.5 Tablespoons of water; mix and let sit for about 10 minutes until it thickens.
How in the world does one make vegan “bacalhau” with leeks? I’d love to try making it. Sounds fascinating!