Prepare Dough:

• Whisk together flour, cocoa powder, and salt in a medium bowl.
  Cream butter and sugar in a stand mixer until light and fluffy (about 3 minutes). Add egg yolks, one at a time, followed by vanilla and almond extracts.
  Reduce speed to low and alternate adding the dry ingredients and milk, starting and ending with the dry mixture.
  Wrap the dough in plastic wrap and refrigerate for at least 1 hour.
  
  Preheat and Assemble:
  
  Preheat oven to 350°F. Line a baking sheet with parchment paper.
  Roll chilled dough into 1-inch balls. Dip each ball into whisked egg whites, then roll in chopped pecans.
  
  Form Thumbprints:
  
  Place coated dough balls on the prepared baking sheet. Use the back of a teaspoon or thumb to press a small indentation into each ball.
  
  Bake:
  
  Bake for 13 minutes. Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
  
  Fill with Caramel:
  
  Spoon caramel sauce into the center of each cookie. Let the caramel set for a few minutes before serving.