Preheat the oven to 180 degrees Celsius. Line 2 baking trays with non stick baking paper.
Beat butter, sugar and vanilla essence until pale and creamy. Add egg and beat until well combined. Add the flour gradually and stir until it is all mixed together properly.
Flour hands. Roll teaspoonfuls of mixture into balls. Place on tray about 5 cm apart. With a lightly floured finger, create a small indention in the centre of each ball. Spoon half a teaspoon into the centre of each biscuit.
Bake for 15 minutes or until golden brown. Wait 30 minutes for biscuits to harden.