I had never ate or made thumbprint cookies, but again I had to make cookies for a kids christmas party....and after using so much chocolate (m&m oatmeal cookies, cranberry white chocolate oatmeal cookies, sweet marie bars, chocolate bark) I decided that perhaps jam might be a nice change and a hit with kids....turns out they like chocolate much more! But they did brighten up the plate with a deep red raspberry jam. The toasted almonds on the outside added a nice crunch and complimented the raspberry flavor really well.
2/3 cup unsalted butter, at room temperature
1/3 cup granulated sugar
2 large egg yolks
1 teaspoon vanilla extract
1/2 teaspoon salt
1-1/2 cups all-purpose flour
2 large egg whites
3/4 cup finely chopped nuts of choice (I used almonds)
1/3 cup jam (any flavor - I used raspberry)
Preheat oven to 350 F. Line baking sheets with parchment paper or a non-stick baking mat. In a large bowl, beat together butter and sugar until light and fluffy. Beat in egg yolks, vanilla extract and salt. Gradually stir in flour.
Form dough into 1-inch diameter balls. Dip in lightly beaten egg whites, then roll in nuts. Place 1 inch apart on prepared cookie sheets. Press down center of each with thumb.
Bake for 16 to 18 minutes, or until golden brown. Cool on baking sheet for 5 minutes, then remove to a wire rack to cool completely. Just before serving, fill centers of cookies with jam. Or, fill centers with 1/2 teaspoon of jam before baking.