Ingredients
6 tablespoons sugar3 tablespoons cornstarch1/4 teaspoon salt1 cup 2% milk6 tablespoons heavy whipping cream1 large egg yolk, beaten, room temperature2 teaspoons vanilla extractCOOKIES:9 tablespoons butter, softened1 cup sugar2 large egg yolks, room temperature1 large egg, room temperature2 teaspoons vanilla extract1/2 teaspoon grated lemon zest1 cup plus 2 tablespoons cake flour1 cup all-purpose flour3/4 teaspoon baking soda1/2 teaspoon salt1/2 cup plus 2 tablespoons buttermilkGLAZE:2 ounces unsweetened chocolate, chopped4 teaspoons butter1/2 cup whipping cream1 cup confectioners’ sugar
Preparation
In a small heavy saucepan, combine the sugar, cornstarch and salt. Stir in milk and cream until smooth. Cook and stir over medium-high heat until thickened and bubbly. Reduce heat to low; cook and stir 2 minutes longer.
Remove from the heat. Stir a small amount of hot mixture into egg yolk; return all to the pan, stirring constantly. Bring to a gentle boil; cook and stir 2 minutes longer. Remove from the heat. Stir in vanilla. Cool for 15 minutes, stirring occasionally. Transfer to a small bowl. Press waxed paper onto surface of custard. Refrigerate for 2-3 hours.
In a large bowl, cream butter and sugar until light and fluffy. Beat in the egg yolks, egg, vanilla and lemon zest. Combine the cake flour, all-purpose flour, baking soda and salt; gradually add to creamed mixture alternately with buttermilk and mix well.
Drop by rounded teaspoonfuls 2 in. apart onto greased baking sheets. Bake at 400° for 5-7 minutes or until firm to the touch. Remove to wire racks to cool completely.
Spread custard over the bottoms of half of the cookies; top with remaining cookies.
For glaze, place chocolate and butter in a small bowl. In a small saucepan, bring cream just to a boil. Pour over chocolate and butter; whisk until smooth. Stir in confectioners’ sugar. Spread over cookies; let dry completely. Store in the refrigerator.
