1: First make the saffron mayonnaise. Warm the olive oil in a small pan over a low heat. Add the garlic and saffron. Cook very gently for 1–2 minutes then add the pastis and water and let the saffron steep in the liquid for 5 minutes. Remove from the heat and cool.
2: Place the egg yolks in a food processor with the mustard and vinegar. Add the infused saffron water and blend together. With the motor running, add the vegetable oil very slowly until it thickens and emulsifies. Season with lemon juice, salt and cayenne pepper, to taste. Transfer to a clean bowl and cover with cling film. Refrigerate until needed.
3: To make the crab fritters, pour the water into a medium-sized saucepan with the butter and heat until the butter melts. Remove from the heat and add the flour. Mix well until fully incorporated. Beat in the eggs one at a time, using a wooden spoon. Alternatively, you can transfer the dough to a stand mixer. Beat on a slow speed to combine the ingredients, then increase it to medium and beat until smooth and cooled a little.
4: Beat in the Gruyère and brown crabmeat. Fold in the white crabmeat, lemon zest, chives, capers and a pinch of salt. Leave to go cold. When cold, with lightly floured hands, roll the mixture into walnut-sized balls and place on a lightly floured tray – you should have about 16.
5: Heat the oil in a deep fat fryer or saucepan to 180°C and lower the balls in gently. Be careful not to crowd the pan – you may need to fry them in batches. Make sure you let the oil come back up to temperature before adding a new batch. Cook until golden brown, about 3–4 minutes. Remove from the fryer, drain on kitchen paper and season with salt and cayenne pepper. Serve immediately with the saffron mayonnaise.