Preheat the oven to 350°F (175°C). In a mixing bowl, combine flour, butter, and powdered sugar until crumbly. Add egg yolk and mix until dough forms.

Press the dough into the bottom and up the sides of a tart pan. Prick the bottom with a fork and bake for 15 minutes or until lightly golden.

In a bowl, whisk together orange juice, sugar, eggs, and orange zest until well combined.

Pour the filling into the baked crust and return to the oven. Bake for an additional 15 minutes or until set.

Let the tart cool, then top with whipped cream and orange slices before serving.