I think of thumbprint cookies as Christmas cookies because that is when my family would make them, but the truth is that they are popular cookies any time of the year.
1/3cupjam, or glace cherries for the thumbprint hollow
Instructions
Preheat oven to 325ºF.
Cream the butter and sugar. Add the egg yolk, flour and vanilla. Shape into small balls.
Dip the balls into the egg white. Roll in nuts. Lay the cookie ball on a baking sheet. Press it down, making an indentation in the center with your thumb or finger.
When baked fill the center of each cookie with jam.