In a medium bowl, whisk together the egg yolk, heavy cream, and a splash of vanilla. In a food processor, combine all-purpose flour, confectioners’ sugar, and kosher salt until well mixed. Add chilled, cubed unsalted butter, processing until the mixture resembles coarse crumbs. Gradually add the egg mixture until a soft dough forms. Wrap in plastic wrap and chill for 1 hour.

After chilling, preheat your oven to 350°F (175°C). Roll out the dough on a lightly floured surface, then fit it into a 9-inch tart pan, trimming the edges as needed. Refrigerate the crust for 15 minutes to prevent shrinking. Once set, blind bake the tart crust for 20-25 minutes, or until golden brown. Let it cool completely before adding the fillings.

In a medium saucepan, whisk together freshly squeezed lemon juice, lemon zest, eggs, and honey. Cook over medium heat, stirring constantly, until the mixture thickens and reaches 165°F (about 5 minutes). Remove from heat and whisk in cold butter until melted and combined. Strain the curd through a fine sieve into the cooled tart shell, ensuring it's smooth. Bake for an additional 10-12 minutes until slightly jiggly.

In a blender, puree blueberries until smooth, then strain the mixture to remove any seeds. In a saucepan, combine the strained blueberry puree with honey and cornstarch, cooking over medium heat. Stir continuously until the mixture thickens, about 4 minutes. Once thickened, pour this luscious layer over the lemon curd. Refrigerate the tart until fully set, approximately 2 hours.

Once set, slice the Blueberry Lemon Curd Tart with Buttery Shortcrust into beautiful wedges. For an extra touch of flair, serve each slice garnished with fresh blueberries or a dollop of whipped cream.