Ingredients for 1 servings:
1. 1 cup cornstarch
2. 1 cup flour
3. 1 teaspoon baking powder
4. 12 tablespoons unsalted butter
5. 3/4 cup sugar
6. 2 egg yolks
7. 1 cup dulce de leche (see Dulce De Leche (Latin American Caramel Spread))
8. powdered sugar

Directions:
1. 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.
2. Reduce the mixer speed to low and add the flour mixture in 3 batches, allowing each batch to become incorporated before adding the next.
3. Form the dough into a disc without handling it too much. Wrap with plastic wrap and refrigerate for at least 1 hour.
4. 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.
5. 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.
6. 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.
7. If desired, sprinkle the finished cookies with powdered sugar.

Enjoy your meal!