In a mixing bowl, combine flour and sugar. Add cold butter and mix until crumbly.

Add egg yolk and ice water, mixing until dough forms. Shape into a disk, wrap in plastic, and refrigerate for 30 minutes.

Preheat the oven to 350°F (175°C). Roll out the chilled dough and fit it into the tart pan.

Prick the bottom with a fork and bake for 15 minutes until lightly golden. Remove from oven and let cool.

In a saucepan over low heat, melt the dark chocolate, stirring until smooth. Remove from heat.

In a bowl, whisk together pumpkin puree, heavy cream, brown sugar, vanilla, cinnamon, nutmeg, and salt. Stir in melted chocolate until well combined.

Pour the filling into the cooled crust, smoothing the top.

Bake for 15-20 minutes until set. Let cool before slicing.