Makes 20 sandwich cookies
Prep Time 10 minutes, plus chilling time and dulce deleche preparation
Baking Time 15 to 20 minutes
2 cups all-purpose flour
1/2 cup confectioner’s sugar
1/4 teaspoon salt
1 cup butter, cubed
1/2 cup confectioner’s sugar, for dusting
FOR THE DULCE DE LECHE
1 (300-ml) can condensed milk
1. Preheat oven to 325°F. Line baking sheets with parchment paper or a silicone mat.
2. Combine flour, confectioner’s sugar, and salt in a food processor. Add butter and pulse until mixture forms into a soft ball.
3. Cover dough with plastic wrap and chill for at least 30 minutes in the refrigerator.
4. Using a rolling pin, roll the dough in between sheets of cling wrap or wax paper until 1/8-inch-thick.
5. Using a cookie cutter or a drinking glass, cut out dough into 11/2-inch rounds. Place on prepared baking sheets.
6. Bake in the preheated oven for 15 to 20 minutes or until cookies are slightly golden around the edges.
7. Dredge cookies in confectioner’s sugar and shake off excess. Let cool completely, then store in an airtight container.
8. Make the dulce de leche: Remove the paper label of the can of condensed milk. Fill a medium saucepan with water. Bring to a boil, then lower heat to a gentle simmer. Place the can in the pot, making sure it is fully covered in water. Simmer for 21/2 to 3 hours, adding water occasionally to make sure that the can is always completely submerged in water.
9. Remove can from water and allow to cool to room temperature before opening, about 2 hours.
10. Transfer dulce de leche to an airtight container. Store in the refrigerator until ready to use.
11. Assemble the cookies: Using an offset spatula, spread one or two teaspoons dulce de leche on the flat side of a cookie. Place another cookie on top to sandwich the filling. Wrap cookies individually in cellophane or wax paper. Store in an airtight container.