Alfajores evolved from alajú, a centuries-old confection originally made with honey, nuts and spices. Although there are variations in every region—some are dipped in chocolate, others rolled in coconut—the tender, buttery cookies are sandwiched with dulce de leche, a thick, milk-based caramel-like spread.
For dulce de leche:
1 300 mL can sweetened condensed milk
1 1/2 cups butter, at room temperature
1 cup sugar
1 tsp. vanilla
3 1/2 cups all-purpose flour
1/4 tsp. salt
Preheat the oven to 400˚F.
To make the dulce de leche, pour the sweetened condensed milk into a pie plate and cover tightly with foil. Place in a 9×13-inch baking pan or roasting pan and add enough water to come halfway up the side of the pie plate. Bake for 1 to 1.5 hours, until the milk is thick and deep golden. Set aside to cool.
To make the cookies, beat the butter, sugar and vanilla for 3 to 4 minutes, until pale and light. Add the flour and salt and beat on low speed or stir by hand just until the dough comes together. Gather it into a ball, divide it in half, shape each piece into a disk and wrap in plastic. Refrigerate for at least half an hour, or up to three days.
When you’re ready to bake, preheat the oven to 350˚F. On a lightly floured surface, roll each piece of dough out 1/4-inch thick and cut into 1 to 1 1/2 inch rounds with a cookie cutter. Place on a parchment lined baking sheet and prick each once or twice with a fork.
Bake for 12 to 15 minutes, or until pale golden, then transfer to a wire rack to cool. Once completely cooled, spread half the cookies with dulce de leche and top with a second cookie. Makes about two dozen sandwich cookies.