1. Make the tart crust: In a food processor, pulse the flour, butter, and 1/4 cup sugar until the mixture resembles coarse crumbs. Add the egg yolk and water and pulse until the dough just begins to come together.

2. Press the dough into a 9-inch tart pan with a removable bottom. Refrigerate for 30 minutes.

3. Preheat the oven to 375°F. Blind bake the tart crust for 15 minutes. Remove the weights and bake for an additional 10 minutes until lightly golden. Allow to cool completely.

4. Make the chocolate filling: In a medium saucepan, heat the cream over medium heat until just simmering. Remove from heat and stir in the chopped chocolate until smooth.

5. In a separate bowl, whisk together the eggs, 1/2 cup sugar, vanilla, and salt. Slowly whisk the egg mixture into the chocolate mixture.

6. Pour the chocolate filling into the prepared tart crust. Bake for 25-30 minutes, until the center is set but still slightly jiggly.

7. Allow the tart to cool completely, then carefully remove the outer ring. Garnish the top with delicate gold leaf just before serving.