Here is a recipe I found, sorry I haven't tried it so I can't tell you if it is good.

Abernethy biscuits

Ingredients

1 cup flour
1/2 cup butter
3 tbsps sugar
1 tsp cream of tartar
1/2 tsp bicarbonate of soda;
1 tbsp milk
pinch of salt

Method

Sift flour, salt, bicarbonate of soda, cream of tartar together. Rub in butter until mixture looks like bread crumbs. Dissolve sugar in milk, stir into butter mixture. Form into stiff dough.;Roll out to a thickness of 1/4 inch. Cut in squares; prick all over. Bake in oven at 350°F (180°C) for 20 minutes.

Serves: Makes about 10 biscuits.