Preheat the oven to 350°F (175°C). In a mixing bowl, combine the flour, powdered sugar, softened butter, and salt. Mix until the dough resembles coarse crumbs.

Press the dough into a 9–10-inch tart pan evenly, pressing up the sides for an even rim.

Place the tart pan on a baking sheet and bake for 15–20 minutes until lightly golden.

While the crust bakes, whisk together the heavy cream, lemon juice, granulated sugar, eggs, and lemon zest in a medium bowl until smooth.

Pour the lemon filling into the warm baked crust and bake for an additional 25–30 minutes until the filling is set but still has a slight wobble.

Let the tart cool to room temperature, then chill in the refrigerator for at least 2 hours.

In a small saucepan, combine the blueberries, water, and sugar. Cook over medium heat, stirring until thickened, about 8–10 minutes.

Optional: For a smooth sauce, blend briefly with an immersion blender.

Serve the chilled tart sliced, drizzled with blueberry sauce.