About 20 years ago, we ran this recipe with a story from reader Charlotte S. Undercoffer: “My mother died when I was 13, and my father’s sister tried to make Christmas special for me and my brother. The most important day before Christmas was the day that we baked Aunt Mae’s thumbprint cookies. After we had mixed all the ingredients, she put the little balls of dough on the baking pan. Then we used our thumbs to make the indentation for the jelly. (It always had to be cherry jelly for us–but any kind is good.)”
To learn more about this recipe, including step by step instructions and additional photos, check out our post on Summer Jam-Filled Thumbprint Cookies.
In the bowl of a standing mixer or, if using a handheld mixer, in a large bowl, beat butter and brown sugar until light and fluffy, about 4 minutes. Add egg yolk, flour, vanilla, and salt and mix well.
Preheat oven to 400 degrees. In a small bowl, beat the egg white until frothy. Put walnuts in another small bowl.
Roll cookie dough into walnut-size balls, then roll each ball in the egg white and then the walnuts. Arrange on two ungreased cookie sheets and press the center of each cookie with your thumb (this is a great activity for young kids). Bake 5 minutes, then reduce heat to 300 degrees. Bake 8 minutes more, then remove the cookies from the oven and check to see if the thumbprints remain. If not (the cookies do tend to puff up), use the handle of a wooden spoon to re-press the thumbprints, then return the cookies to the oven until they’re light golden brown, 5 to 7 more minutes.
Remove from oven and cool at least 30 minutes, then spoon a bit of jam into the center of each cookie.