In a large bowl, whisk together the almond flour, gluten free all purpose flour, baking powder, and salt.
Add the cold cubed butter to the dry ingredients, and using a pastry cutter or your fingers, work the butter into the flour mixture until it resembles coarse crumbs.
Gradually add the beaten egg to the mixture, stirring until a dough forms.
Gently knead the dough on a lightly floured surface, then roll it out to about 1/2 inch thick.
Use a cookie cutter or glass to cut out circles, then transfer them to a parchment lined baking sheet.
Repeat with remaining dough, and place the baking sheet in the refrigerator for at least 30 minutes.
Preheat your oven to 350°F (175°C), and bake the cookies for 12 14 minutes or until golden brown.
Allow them to cool completely on a wire rack.
To assemble, spread a thin layer of dulce de leche on the flat side of one cookie, then top it with another cookie to form a sandwich.
Pipe or spoon vanilla custard on top of the assembled cookie and enjoy!
Chef’s Insight
The key to achieving perfect flaky layers is to work the butter into the dough until it resembles coarse crumbs.
Notes
If you prefer a softer alfajor, reduce the baking time to 10 minutes.