Yogurt Lemon Bars

RECIPE

Preheat oven to 400°F.
On a floured surface, roll out puff pastry to 11x16". Cut in half lengthwise and place both halves on an ungreased baking sheet. Pierce pastry with a fork in several places.
Bake pastry puff for 7-10 minutes or until puffed and golden. Cool on a rack.
In a medium bowl, blend confectioners sugar, cornstarch, egg yolks, sugar, vanilla, and 2 tablespoons of the milk with a whisk. Set aside.
Bring remaining milk (3/4 cup + 2 tablespoons) and 2 ½ cups yogurt to a boil in a medium saucepan, while whisking.
Stir hot milk and yogurt mixture into sugar and cornstarch mixture, blend thoroughly. Return mixture to saucepan.
Cook. Stir constantly over medium heat for 4-5 minutes or until thickened to pudding consistency.
Remove from heat and stir in lemon zest. Refrigerate mixture for 20 minutes.
On a cutting board, spread the thickened, slightly cooled mixture on one piece of the pastry. Refrigerate for another 20 minutes, or until set.
Frosting: Combine the yogurt and confectioners sugar in a small bowl. Set aside.
Lemon bars: Place a plain piece of the puff pastry on top of a piece with filling in it. Frost. Chill until ready to serve.
Slice into 10 bars. Top with berries or sprinkle with some confectioners sugar if desired.