Chocolate Peppermint Bark Pretzel Cookies

In a large mixing bowl, beat butter, 1 1/2 cups sugar, egg yolks, milk and extracts until fluffy.
In a separate bowl, stir together flour, cocoa and salt. Gradually add flour mixture to butter mixture, beating until blended.
Refrigerate dough at least 1 hour, or until firm enough to handle. (If you are a little short on time, you can also freeze for about half the time.)
Preheat oven to 350u0b0F. Lightly grease a cookie sheet or line with parchment paper.
Place extra sugar (start with about 2/3 cup) in a small bowl and if desired, add some sparkling sugar.
With the palms of your hands, roll dough into 1 1/2 to 2 inch balls. Coat in sugar, and place on prepared cookie sheet, spaced about 2 inches apart. Flatten cookie dough balls slightly.
Bake for 10-12 minutes, or until set. Remove from oven and immediately place 1 peppermint bark pretzel on top of each cookie (see note below). Transfer cookies to wire rack to cool.
Note: Feel free to experiment around with the toppings! Take a look near the end of my blog post for some ideas. If you would like to make a glaze, here's what you need to do: Before baking, instead of flattening slightly, press thumb gently in center of each cookie. Let cookies cool slightly before spooning glaze in the center. To make glaze, in small bowl whisk together 1/2 cup powdered sugar, 1 tablespoon softened butter, 2 teaspoons milk, and 1/4 teaspoon vanilla extract (or peppermint extract) and whisk until smooth.