In a food processor, combine flour, confectioners' sugar, and salt. Pulse briefly to mix. Add chilled butter and process until resembling coarse crumbs, about 10 seconds. Incorporate egg yolk and heavy cream, then process until a dough forms. Shape into a disk, wrap in plastic, and refrigerate for 1 hour.

Preheat oven to 375ºF (190ºC). Roll dough into an 11-inch circle and fit into a 9-inch tart pan, trimming edges. Freeze for 30 minutes. Line with foil, fill with weights, and bake for 30 minutes. Remove weights and bake for an additional 5 minutes until golden. Let cool completely.

In a saucepan, whisk lemon juice, lemon zest, eggs, honey, and salt. Cook over medium-low heat, stirring constantly, until thickened to 165ºF (74ºC), about 10-12 minutes. Remove from heat, stir in butter until melted and smooth. Strain curd and pour into cooled tart shell.

Blend blueberries until smooth. Strain through a sieve to remove seeds. In a saucepan, combine blueberry puree, honey, cornstarch, and water. Cook over medium heat until thick and bubbly, about 5 minutes. Remove from heat, add a tablespoon of reserved lemon juice, and spread over lemon curd in tart shell.

Refrigerate tart for at least 2 hours to allow layers to set. Tart should be set yet slightly wobbly in the center when ready to serve.