In the bowl of a food processor, pulse together flour, salt, and sugar.

Cut in cold butter using the food processor or your fingers until crumbly with some pea-sized bits.

Add egg yolk and ice water 1 tbsp at a time, until the dough just holds when pinched.

Form into a flat disk, wrap, and refrigerate for at least 1 hour (or up to 2 days).

Preheat oven to 375°F (190°C).

Roll out chilled dough on a floured surface into a 12-inch circle. Fit into a 9-inch pie dish.

Trim and crimp the edges, then chill again for 15 minutes.

Prick bottom with a fork, line with parchment, and fill with pie weights or dry beans.

Bake for 15 minutes. Remove parchment and weights. Bake 5–7 more minutes until lightly golden. Let cool slightly.

Heat cream in a small saucepan until steaming (not boiling).

Pour over chopped chocolate and butter in a bowl. Let sit 1 minute, then stir until smooth.

Add a pinch of flaky salt if desired.

Spread ganache over bottom of baked crust and chill for 10–15 minutes to set.

In a large bowl, whisk together pumpkin, eggs, brown sugar, maple syrup, spices, and salt.

Whisk in half-and-half until smooth and well combined.

Preheat oven to 350°F (175°C).

Gently pour pumpkin filling over the chilled ganache layer. (Optional: swirl in some reserved chocolate ganache into the pumpkin filling for a pretty effect.)

Bake 45–55 minutes, or until filling is mostly set with a slight jiggle in the center.

Let cool completely at room temperature, then refrigerate for at least 2 hours (or overnight) before slicing.