3. Mix in flour, vanilla and salt. Mix until smooth.
4. Divide the batter among the muffin-top pan (approximately two tablespoons of batter per muffin-top cup), spreading evenly with an offset spatula. (Note: If you do not have a muffin-top pan, you can use a whoopie pie pan or spoon two tablespoons of batter two inches apart onto a parchment paper-lined baking sheet.)
5. Bake cookies until just pale golden, 15 to 20 minutes. Remove from oven, and let cool.
6. In the meantime, whisk together the ingredients for the chocolate glaze and the vanilla glaze (each glaze in a separate bowl) until smooth.
7. Transfer the cookies to a wire rack.
8. Using a spoon, coat 1/2 of each cookie in the white glaze. Allow to air dry for about 10 minutes.
9. Spread chocolate glaze on the other half of the cookie.
10. Let set for about one hour, and enjoy!