Blueberry Topping

1. Place sugar and 1/2 cup blueberries in a small nonreactive saucepan and cook over low heat. Add 1 teaspoon water to cornstarch and stir until smooth. Add cornstarch mixture to berries and sugar stirring constantly until the mixture comes to a boil and thickens slightly. Remove from heat and cool completely. Fold remaining whole berries into cooked, cooled mixture.

Cream Cheese Pastry Cream

1. Combine 1/2 cup milk and 2 tablespoons sugar in a medium saucepan. Bring just to a simmer over medium heat. Remove from heat. In a medium bowl, whisk yolks, cornstarch and remaining 2 tablespoons sugar together. Add remaining 1/4 cup cold milk and whisk until smooth.
2. Add 1/4 cup hot milk mixture to egg mixture while whisking continually. Add another 1/4 cup, then add egg and milk mixture back to remaining hot milk in saucepan. Bring to a boil, stirring constantly. Cook 1 to 2 minutes, until thickened. Remove from heat, add cream cheese and vanilla and whisk until smooth. Strain into a bowl and cover the surface directly with plastic to prevent a skin from forming. Refrigerate.

Assembly

1. Whisk pastry cream until smooth and spoon into tart shell. Smooth surface and top with berries. Sprinkle with lemon zest and finishing sugar. Chill slightly before serving to allow tart to set up, making it easier to cut and plate.

Cornmeal Shortbread Crust

1. Cream butter with confectioners' sugar and lemon zest in the bowl of an electric stand mixer fitted with the paddle attachment until smooth and lighter in color. Add egg and beat to combine.
2. Combine all-purpose flour, cornmeal and salt in a medium bowl. Add flour mixture to butter mixture in 2 batches, scraping down the sides of the bowl between additions. Mix until well combined.
   
   Form dough into two disks for a 4 by 12-inch rectangular tart, and wrap both disks with plastic wrap. Freeze one disk for use another time, and chill the other at least 1 hour or until firm. (For an 11-inch round tart, form dough into a disk, wrap with plastic wrap and chill 1 hour.)
3. Lightly flour a work surface and roll out dough to an 8 by16-inch rectangle. Use dough to line a 4 by 12-inch tart pan with a removable bottom, prick all over with a fork and chill 30 minutes.
4. Preheat oven to 325°F. Bake until deep golden brown, about 20 minutes. Cool on a wire rack.