How to cook
Preheat the oven to 428°F (220 degrees).
Grease 2 baking trays.
Beat the butter and sugar into a fluffy cream and then add the vanilla essence.
Add the egg whites, one at a time. Lastly, pour the flour into the mixture, then beat everything very well until you a smooth dough forms.
Pour it into a decorating tube and pipe out the biscuits into the trays.
Leave space between the biscuits because they will increase in volume during baking.
Bake them for 10-15 minutes.
Leave them to cool and serve them.