Lemon butter biscuits

1.Grease and line two large oven trays with baking paper.

2.Beat butter, sugar, rind and vanilla in a small bowl of an electric mixer until light and fluffy. Transfer to a large bowl. Add flour. Stir until combined. Roll tablespoons of mixture into balls. Place about 4cm apart on trays.

3.Cook in a moderately slow oven (160C) for about 20 minutes, swapping trays halfway, or until lightly golden. Cool on trays.

4.Dip tops of biscuits into icing, allowing excess to drip away. 
Stand on a wire rack to set.

5.To make lemon icing, place sugar and rind in a small heatproof bowl. Sit bowl over a saucepan of simmering water. Stir in enough lemon juice 
to form a thick consistency. 
Remove bowl from heat.