1/2 lb unsalted butter
room temp
3/4 cup granulated sugar
3 each egg yolks
1 1/2 tsp triple sec or rum
1/2 tsp vanilla extract
2 tsp lemon zest
1 2/3 cups all-purpose flour
2 1/2 cups cornstarch
1/2 tsp baking soda
2 tsp baking powder
8 oz bittersweet chocolate
3 Tbsp water
3 each large egg yolks
1/4 cup powdered sugar
2 Tbsp Frangelico
1 1/2 cups cold heavy cream
1 can sweetened condensed milk
powdered sugar for dusting
  • large pastry bags
  • Extra stainless steel bowls
  • Stand mixers or electric mixers
  • candy thermometer
For the Cookie Dough
Preheat the oven to 350F. In the bowl of an electric mixer fitted with a paddle attachment, paddle the butter and ¾ cup sugar until they are well combined. Mix in the egg yolks one at a time, then add the liquor, vanilla extract, and lemon zest. In a mixing bowl, sift together the dry ingredients. Add to the butter/sugar mix and paddle on low speed until a dough forms. Remove to a clean table and shape into 1 ½ inch thick logs. Cover tightly with plastic wrap and chill for 30 minutes.
Cut ¼ inch thick rounds from the logs to shape the cookies. Place cookies on an ungreased baking sheet and bake for 15 - 20 minutes, or until the edges just barely begin to brown. Set aside to cool.
For the Chocolate Mousse
Melt chocolate over a double boiler of simmering water, stirring until smooth. Remove from heat and keep warm. Separately, beat cream to soft peaks. In a third, separate bowl, whisk together water, yolks, and powdered sugar. Heat over a double boiler of simmering water and whisk constantly until mixture is frothy and thickened, and a candy thermometer registers 160°F, about 6 minutes. Add the Frangelico. Remove from heat immediately and use an electric mixer to whisk until slightly cooled to about 110F. Fold into the warm chocolate. At this point, be sure that the chocolate mixture is warm to the touch, about 110F, otherwise it may set too quickly when adding the cream, creating big flecks of chocolate in the mousse. If it’s too cool, stir over hot water to warm it.
For the Caramel
Place the unopened can of sweetened condensed milk in a tall pot and fill with water. Bring to a boil over high heat, then reduce to a gentle boil. Cook for 3 hours, topping off with hot water as needed to keep the can submerged. Remove from the water and set aside to cool. Open can only when cooled and empty into a bowl. Beat briefly to soften. Spread caramel on one cookie and top with another to make alfajores.
To Serve
Pipe the mousse into a glass and serve with alfajores. Dust with powdered sugar if desired.