Sift together flour, baking powder and salt, set aside. Cream together butter and sugar then beat in eggs. Stir in sesame seeds. Stir in flour mixture and water gradually. Cover and chill for 3-4 hours.
Preheat oven to 190 degrees C. Drop chilled dough from teaspoon onto ungreased baking tray. Flatten with a glass that is covered with a damp tea towel. Bake until light brown around the edges, about 10 minutes.
These are plain. You can flavour the dough with vanilla, nutmeg or mixed spice. You can top with extra sesame seeds after flattening.