Start heating your oven to 180 C / 350 F / Gas Mark 4.
Put all the dry ingredients into a bowl. Mix well with a fork, then cut the butter in. In a separate bowl, beat the eggs with the vinegar, then pour into the flour mixture and stir. Turn the dough out onto a floured surface. Knead it slightly, and roll out to 1/4 inch (1/2cm) thick. Use a floured cookie cutter or rim of a glass to cut into 3 inch (7 cm) rounds.
Place on the cookie sheet, prick with fork. Bake 20 to 25 minutes or until lightly browned. Remove from oven, place on rack, and while warm sprinkle with icing sugar.
Use malt or cider vinegar or, failing that, white vinegar.If you don't have any particular spice that is listed, click on a spice for suggested substitutes, or just omit.