Soak the chickpeas overnight in cold water. Add the bay leaf and 2 teaspoons of salt, cover and cook over a medium flame until the chickpeas are tender (about 1 1/2 hours), adding more water if necessary. Drain well.
In a small mixing bowl put the egg yolks and into this, beat the oil and vinegar with a wire whisk. Stir in the onion, garlic, 2 tablespoons of the parsley, capers and chickpeas. Refrigerate overnight.
Allow to come to room temperature before serving and just before serving sprinkle over with the remaining parsley.