1 4 ouncestick unsalted butter, at room temperature
4 ouncescream cheese, at room temperature
1/2teaspoonpure vanilla extract
1 egg yolk
1 cupplus 2 tbsp flour
1 (about 11 oz) jar prepared lemon curd
Using an electric mixer, cream the butter, cream cheese and sugar on high speed for 3 minutes.
Add the vanilla, egg yolk and salt and mix at low speed until blended. Mix in the flour at low speed until incorporated.
Halve the dough and pat into 2 squares. Wrap in plastic wrap; refrigerate for 30 minutes.
Preheat the oven to 350 degrees . Line 2 cookie sheets with parchment. Remove the parchment from 1 cookie sheet and dust with flour. Roll out 1 dough square into a 7-by-11-inch rectangle about 1/8 inch thick.
Transfer the parchment and dough to the pan; refrigerate while you repeat with the remaining parchment and dough.
Using a fluted pastry wheel, trim all sides of the chilled dough to even out, then cut into 15 squares. Separate the squares on the pan. Bake until light brown on the edges, 11 to 12 minutes. Transfer to racks to cool. Repeat with the remaining dough.
Sandwich the cookies with lemon curd; dust with confectioners sugar.