Alfajores (South American Dulce De Leche Sandwich Cookies)

While they have origins in Moorish Spain, alfajores are especially popular in South America. They are simple shortbread sandwich cookies with a sweet filling of dulce de leche. Different doughs are used for the cookies depending on the country. Some use normal flour dough, while others add cornstarch or even cassava flour for a more delicate crumb. This recipe uses a mixture of flour and cornstach.

Makes 20 cookies

Ingredients
1 cup Cornstarch
1 cup Flour
1 teaspoon Baking powder
12 tablespoons (1 1/2 sticks) Unsalted butter
3/4 cup Sugar
2 Egg yolks
1 cup Dulce de leche

Method
Sift the cornstarch, flour and baking powder together in a medium bowl. In a mixer bowl, beat the butter and sugar together until light and fluffy. Add the egg yolks, beating until they are incorporated.
Reduce the mixer speed to low and add the flour mixture in 3 batches, allowing each batch to become incorporated before adding the next.
Form the dough into a disc without handling it too much. Wrap with plastic wrap and refrigerate for at least 1 hour.
Preheat oven to 350°F. Remove the dough to a lightly floured work surface and roll out to about 1/8-inch thick. Cut out 40 2-inch rounds, and carefully place the rounds on two lightly greased cookie sheets.
Bake for 9 to 10 minutes, but not so long that they begin to brown. Remove from the oven and cool for 5 minutes. Then remove the cookies to wire racks and cool completely.
Spread about 2 teaspoons of dulce de leche on the flat half of a cookie and cover it with the flat half of another cookie to form a sandwich. Repeat with the remaining cookies. If desired, sprinkle the finished cookies with powdered sugar.

Variations
For extra flavor, try adding one or more of these to the dough when you add the eggs: 1 teaspoon vanilla or almond extract; 1 tablespoon of brandy or cognac; 1 tablespoon of lime or lemon zest.
Use more dulce de leche on each cookie so that some squeezes out the sides. Then roll the edges in grated coconut or ground nuts.
Fill the cookies with your favorite jam instead of dulce de leche.