I sometimes use the back of a spoon to re-do the thumb indentation right after they come out of the oven.
2/3 c. butter or margarine
½ c. sugar
2 eggs, whites and yolks separated (slightly beat the whites)
1 tsp. vanilla
1 ½ c. flour
1 c. finely chopped walnuts
1/3 to ½ c. fruit preserves or jam of your choice (I especially like raspberry or apricot)
1. Preheat oven to 375°. Grease a cookie sheet; set aside. In a large mixing bowl beat butter or margarine with an electric mixer on medium to high speed for 30 seconds. Add the sugar and beat till combined, scraping sides of bowl occasionally. Beat in egg yolks and vanilla till combined. Beat in as much of the flour as you can with the mixer. Stir in remaining flour. Cover; chill dough about 1 hour or until easy to handle.
2. Shape dough into 1” balls. Roll balls in egg whites, then in walnuts. Place 1 inch apart on the prepared cookie sheet. Press your thumb into the center of each ball. Bake for 10 to 12 minutes or till edges are lightly browned. Transfer cookies to a wire rack and let cool. Just before serving, fill centers with jam or preserves.
Yield: about 42 cookies