From 1922:

Take ½ lb. flour, 1 teaspoonful baking powder, ½ teaspoonful essence almonds, 4oz. butter, 3oz. sugar, 1 yolk of egg, 2oz. almonds (blanched, chopped, and toasted), enough warm water to mix. Method: Sift flour and baking powder, cream butter and sugar, add egg, and mix well; then add almond essence, flour, baking powder, and a few teaspoonfuls water if needed. Mix to a stiff dough, turn on to a slightly floured board, roll out, trim the edges, brush over with white of egg, and sprinkle with the chopped almonds. Cut into fingers, and bake in a moderate oven 10 to 15 minutes.