four to five 3-inch, nonstick tart shells or mini pie dishes
For the crystallized lemon: Prepare the garnish first so it has time to crystallize while you make the pie. Using a curly zester, zest the lemon into curly strips. On a plate, toss the zest in sugar and spread out evenly. Set aside and allow to crystallize.
For the sweet crust: Using an electric stand mixer, mix the butter, flour and sugar on low speed until it is incorporated and makes pebbles. Then add the egg and salt, and continue to mix just until it's combined.
Using your hands, form the dough into a small disc. Wrap in plastic wrap and allow to rest in the refrigerator for 30 minutes.
Preheat the oven to 365 degrees F.
Dust a rolling pin and surface with flour. Roll the dough out thinly to 1/4 to 1/8 of an inch. Continue to dust with flour as the dough becomes sticky. Cut out circles slightly larger than the size of your tart shells. If you can't find 3-inch tart shells, just use the next smallest size you can find and adjust your dough cut outs accordingly.
Lay the sweet crust in the shells and trim any excess along the edges. Then line it with parchment paper and weigh it down with pie weights, coffee beans or dry beans. Place the shells on a baking sheet. Bake until golden brown, 10 to 12 minutes. Remove and let cool.
For the blueberry compote: In a saucepan over low heat, add about a third of the blueberries, the sugar and juice of 1 lemon. Reserve the remaining blueberries. Using the back of a knife, scrape out the vanilla seeds and add the seeds and pod to the saucepan. Stir and continue to cook until the blueberries break down and the compote has a syrupy consistency, 5 to 10 minutes.
Create an ice bath by placing a mixing bowl into a larger bowl filled with ice. Pour the compote into a strainer over the mixing bowl. Use a rubber spatula to help work the compote through the strainer. Let the compote cool until it's cold to the touch.
Once the blueberry compote has cooled, add the compote to the remaining blueberries and gently mix together to create your pie filling.
For the chantilly cream: Add the heavy cream, confectioners' sugar, vanilla and the zest from 1 lemon to an electric mixer. Mix until peaks start to form.
Add the blueberry filling to the cooled pie shells and top with the chantilly cream. Garnish with crystallized lemon on top. Serve and enjoy!