Cream butter and sugar until light and fluffy. Add egg yolk and all other ingredients, except cherries. Knead well with hands or spoon. Shape in small balls with hands dusted with confectioners’ sugar.
Put on baking sheet 3″ apart. Press half a candied cherry in center of each cookie. Bake in moderate oven (350 F) until golden brown, about 15 minutes. Cool on racks.