Heat oven to 375° F. Unfold the sheet of pastry on to a parchment-lined baking sheet.

Using the tip of a knife, score a 1-inch border around the pastry without cutting all the way through. Brush the border with the egg and sprinkle with the granulated sugar. Bake until golden and puffed, about 20 to 22 minutes.

Using the tip of a knife, rescore the border of the cooked pastry without cutting all the way through. Gently press down on the center of the pastry sheet to flatten it. Let cool to room temperature, 15 to 20 minutes.

Meanwhile, beat the cream cheese until smooth with an electric mixer. Add the cream, lemon zest, and the confectioners’ sugar, beat until smooth. Spread the cream cheese mixture evenly within the borders of the pastry.

Arrange the blueberries in a single layer over the filling and sprinkle with more of powdered sugar.