Thumbprints are a favorite for many when it comes to holiday cookie assortments. For this variation on a classic, we've chosen the decadent flavor combination of chocolate and caramel, dressing it up with chopped nuts for a rich, buttery, gooey treat.
Preheat the oven to 350°F. Grease (or line with parchment paper) two baking sheets.
Beat together the butter, sugar, salt, and vanilla until smooth and creamy.
Stir in the cocoa and flour.
Shape the dough into walnut-size balls (a tablespoon cookie scoop is helpful here).
Dunk the balls in the egg white mixture, then roll them in the chopped nuts.
Space the balls evenly on the baking sheet, leaving about 2" between them.
Press your thumb into the center of each ball, flattening it out slightly and creating a pocket. Place a cube of caramel into each pocket.
Bake the cookies for 8 to 10 minutes, until the edges are set and the caramel has pooled slightly in their centers.
Remove the cookies from the oven, and allow them to cool on the pans. Allow to cool completely before serving.
