These are really easy and fun cookies to make. The best combination is the soft chocolate with the crumbly cookie. The cornstarch gives the dough a smooth texture that makes it easy to work with and produces a tender, crumbly cookie.
In a large mixing bowl add the flour, cornstarch, baking powder, baking soda and salt.
In an electric mixer beat the sugar and butter until light and fluffy. Add the yolks and add the brandy, lemon zest and vanilla until all mixed in. Add the flour mixture and continue beating.
Once the mixture becomes more dough-like, divide the dough in half and roll each one into logs. Wrap the logs in plastic and place in the refrigerator for about 2 hours.
Heat the oven to 350ºF.
Place parchment papaer on 3 baking sheets. Remove the logs from the fridge and slice into rounds.
Place each round on the sheet pans and bake until edges become slightly golden, about 5 minutes.
Remove from oven and let cool.
Spoon the dolce de leche indo a zipper bag and cut off the corner OR place in a pastry bag.
Flip half of the cookies upside down and place the doce de leche onto the cookies. Top with the remaining cookies and dust with powdered sugar.