Cream the butter and sugar together, until pale and fluffy.
Add the egg yolks and beat well.
Stir in the flour, Schwartz for Chef Caraway Seeds and lemon zest and mix until a firm dough is achieved. Add the water if the mixture is too dry and crumbly.
Knead lightly on a lightly floured surface and roll out to about 0. 5cm (¼ inch) thickness. Cut out 6cm (2½ inch) rounds with a fluted cutter, and place on greased baking sheets.
Bake for 15 minutes until lightly browned and firm to the touch. Transfer to racks to cool and dust lightly with caster sugar. Store in an airtight container to retain crispness.
