Sift the flour, baking powder and salt together. Set aside.

Cream the butter and sugar in an electric mixer.

Add the egg and vanilla, beating until thoroughly blended.

Gradually add the flour mixture to the butter mixture, beating just until blended.

Shape the dough into a ball, cover and place in the fridge for an hour.

Preheat the oven to 375°F (190°C or 170°C for fan ovens).

Pour the decorating sugar on a plate.

Divide the dough in half, leaving half in the fridge. Roll tablespoons of dough between your palms to make balls.

Roll each ball in green coloured sugar.

Place on ungreased baking sheets about an inch apart. Gently press the tops just to flatten a little bit.

Repeat with the second half of the dough.

Bake for 12 to 15 minutes or until just beginning to turn golden on the edges.

Remove the baking sheets from the oven. Allow the cookies to cool for five minutes before carefully removing them. Cool on wire racks.