Deena Abraham was looking for cookies her grandmother use to make for her. This is a version that I made back in the 60s for my children. It is from a cookbook published by a chapter of the National Council of Jewish Women in 1956.

Cream butter and sugar. Add egg yolk and beat. Add flour and mix thoroughly. Form into small balls - about the size of a walnut. Roll in slightly beaten egg white and then in nuts. Make indentation in center of cookie with a thimble. Bake in 350 degree oven for 8 minutes. Remove cookies and press center again. Bake another 10 minutes. When cool fill centers with your choice of jam or jelly or thin butter cream frosting tinted as many colors as suits you. I usually did some with jelly and the others in pink, green and blue frosting. Use a metal thimble - the plastic could melt when hot.