Place the flour and salt in a food processor. Pulse 3-4 times to combine. Add the butter and continue pulsing until the butter is chopped up and the mixture looks like coarse cornmeal. A few larger pieces are fine.
With the machine running, swiftly add the cold water. Immediate stop the machine when the dough comes together.
Turn the dough out onto plastic wrap and flatten into a thin, round disk. Wrap and place in the refrigerator for at least 30 minutes or up to 3 days.
On a light floured surface, roll the dough to approximately 12 inches in diameter. Gently place in the tart pan. If using a fluted pan, use your thumb to gently press the dough into the flutes. Trim away any excess dough, leaving a slight overhang to account for oven shrinkage. Chill for an additional 30 minutes while preheating the oven to 375 degrees F.
Use a fork to prick numerous holes in the bottom and just up the sides of the dough (not all the way through to the pan). Line the pan with foil and weigh down with dried beans. Place on a baking sheet and bake for 20 minutes, or until the tops are firm. Carefully remove the foil and beans, then continue baking for another 10 minutes or until the dough is firm on the bottom. Allow to cool.
Prepare the blueberry topping:
Remove 1/2 cup of frozen blueberries, and place in the refrigerator to thaw. The cooked berries will lose some of their shape, and these will serve as a garnish. (Note: if making the topping several days in advance, leave these blueberries in the freezer until the day of serving).
Place the remaining blueberries, sugar, and lemon zest in a medium-sized saucepan. Stir to combine. Allow the mixture to sit for 15 minutes, giving the blueberries a chance to thaw slightly and macerate with the sugar.
Turn the heat to medium. As liquid fills the pan, turn the heat up to high and bring the mixture to a boil, stirring periodically. Reduce the heat to medium-low and simmer, stirring periodically, until the liquid has thickened up, approximately 10 minutes. Allow to cool for 5 minutes, then place in the refrigerator to chill.
Prepare the lemon curd whipped cream:
In a medium-sized saucepan, whisk together the egg, yolks, and sugar until smooth. Place the cornstarch in a small bowl or ramekin and whisk in a small amount of the lemon juice to create a slurry. Add the slurry and remaining lemon juice to the saucepan, and turn the heat to medium.
Whisking constantly, cook until the curd has thickened, approximately 5-7 minutes. Remove from the heat and whisk in the butter until the curd is shiny and smooth. Allow to cool for 5 minutes. Transfer to a clean bowl, press plastic wrap directly against the curd to prevent a film from forming, and place in the refrigerator until cold.
Once the curd is cold, transfer to a large bowl. Using a spatula, stir vigorously for several seconds to loosen it up. In a separate bowl, whisk the cream until it reaches a stiff peak.
Stir approximately 1/3 of the whipped cream into the curd, then fold in the remaining whipped cream until evenly combined.
Spread evenly into the tart pan, and top with the prepared blueberry mixture. Sprinkle the reserved 1/2 cup wild blueberries on top.
I used a Wilton Nonstick Round Tart Quiche Pan, 9 by 1 1/8 Inch. A 9-inch pie pan (not a deep dish pan) will also work.You can prepare the tart shell, lemon curd, and berry filling up to 3 days in advance. I recommend not adding the whipped cream to the lemon curd or building the tart too far in advance, as whipped cream can deflate after a few hours. 2-3 hours before serving is a safe estimate.