In a food processor, combine all-purpose flour, confectioners' sugar, and salt. Pulse in cold unsalted butter until crumbly. Mix egg yolk with cold water and add to flour mixture, pulsing until combined. Roll out dough, place in tart pan, and chill in the freezer for 30 minutes.

Preheat the oven to 375°F (190°C). Line the chilled crust with parchment paper and fill it with pie weights. Bake for 30 minutes, then remove weights and parchment. Return to oven and bake for an additional 5 minutes until golden brown. Allow the crust to cool completely.

In a medium saucepan, whisk together lemon juice, zest, egg yolks, honey, and salt. Cook over medium heat, stirring until thickened and reaching 165°F (74°C). Remove from heat, stir in unsalted butter until melted, and strain through a fine sieve into a bowl.

Pour the lemon curd into the cooled tart crust and spread evenly. Preheat the oven to 350°F (175°C) and bake for 10-12 minutes until just set. Let the tart cool completely before adding the blueberry layer.

Puree two cups of blueberries in a blender. Strain the puree through a fine sieve. In a saucepan, mix strained puree with honey and cornstarch and cook over medium heat until thick and bubbly. Stir in a splash of reserved lemon juice.

Spread the thickened blueberry layer over the lemon curd. Cover with plastic wrap and refrigerate for at least 2 hours to set. Garnish with fresh blueberries before serving.