Pour the oil into a tall mixer glass where you can use the hand blender: add the egg and all the ingredients indicated in the recipe. Deep the blender to the bottom, turn it on and hold it still, when all the oil has been incorporated, start moving it up and down until the mayonnaise is homogeneous and well whipped.
Cover the cream and transfer it to the refrigerator for at least three hours: if you can prepare it the day before, it is even better.
Take your vol au vent and with the help of a sac-a-poche with a star spout, start filling them (if you don’t have one, use a teaspoon). Garnish with chives cut with scissor.
If you want to make vol au vent instead of buying them ready, look at the procedure in the recipe for “Puff pastry baskets with turnip greens, stracciatella and quail egg” in the vegetarian menu.