Sift together the flour and salt. Cut in the butter;add the brown sugar, the granulated sugar and sherry or brandy flavoring. Chill for one hour in a plastic wrap. Roll out the dough 1/4 inch thick and cut into 2 1/2 by 1 inch fingers. Prick with fork, brush with the beaten egg and sprinkle with sugar. Transfer by spatula to buttered baking sheet and bake in 375 degree oven for 15 minutes. Cool . Makes about 36 cookies.