Put the egg yolks in a bowl with a little salt and pepper. Slowly stir the oil into the egg yolks with a whisk so that it emulsifies. Season the mayonnaise with vinegar, salt and pepper.
Peel the avocado and remove the stone. Puree with the tuna. Fold in enough of the mayonnaise until the desired consistency is achieved. Finally, add lemon juice to taste.
Depending on the consistency, a piping bag can be used for serving.
Tip:
The cream tastes delicious on its own, but is better and prettier with fried prawns or crabs. I serve them on toasted bread slices, decorated with a fried gamba and a ring of lemon peel as a side dish to the salad.