01 - In a food processor, pulse together flour, powdered sugar, and salt. Add cold cubed butter and pulse until mixture resembles coarse crumbs. Incorporate the egg yolk with a brief pulse. Gradually add ice water, one tablespoon at a time, until the dough just comes together.
02 - Press the dough evenly into a 9-inch tart pan with a removable bottom. Refrigerate for 30 minutes to firm.
03 - Preheat oven to 375°F. Line the chilled crust with parchment paper and fill with pie weights or dried beans. Bake for 15 minutes, then remove weights and bake an additional 8 to 10 minutes until the crust is golden. Allow to cool slightly.
04 - Whisk granulated sugar and citrus zest in a bowl to release essential oils. Add eggs, citrus juice, heavy cream, melted butter, and a pinch of salt. Whisk until smooth and fully combined.
05 - Pour the filling into the warm crust and bake at 325°F for 25 to 30 minutes until filling is just set yet slightly wobbly in the center.
06 - Allow the tart to cool completely in the pan. Refrigerate for a minimum of two hours before serving to ensure proper setting.
07 - Optionally, top with whipped cream and fresh citrus slices or zest to enhance presentation and flavor.