This recipe is one Steve mentioned in one of his comment about Louise. Mother got it from Mrs. Pattison (who was Mrs. Pattison?). I have keyed in this recipe exactly as Mother had written it.
Cream 1/2 cup buter, add gradually 1/2 c sugar; add 1 beaten egg yolk, beat the mixture well. Add 3 T milk, add 1 1/2 c flour which have been sifted with 1 1/2 t Bkg Pdr. & 1/8 t salt: add 1/2 t vanilla. Divide dough into halves. To 1/2 add 1 sq chocolate - melted. Roll each half out thin. Place one on top of other, roll up & slice off.
(The remainder is up to you, i.e temp of oven, how long to bake, grease the cookie sheet, etc.)