Sift the flour, spices and sugar into a basin and rub in butter. Dissolve the bicarbonate of soda in warm milk. Add the egg and beat until blended. Stir into the dry ingredients, and knead until smooth. Flour the hands lightly, and roll equal-sized small portions of dough into balls. Place well apart on a greased baking sheet. Press each ball lightly on top. Bake in a moderate oven, 350°F, 180°C, gas mark 4 for twenty-five minutes. Leave on the baking sheet until they cool. Makes 24-30.