Add the flour, sugar, and salt to a food processor. Pulse briefly to combine.

Cut the cold butter into cubes and add it to the food processor. Pulse until the mixture resembles coarse crumbs.

With the food processor running, add the ice water one tablespoon at a time. The dough will still look crumbly, but it should hold together when pressed between your fingers.

Transfer the dough to a clean work surface and gently bring it together into a ball. Wrap in plastic wrap and refrigerate for at least 30 minutes.

Preheat the oven to 350°F (180°C).

Roll out the chilled dough on a lightly floured surface and carefully transfer it to a 9-inch pie dish.

Line the crust with parchment paper and fill with pie weights, dried beans, or uncooked rice.

Bake for 20 minutes. Carefully remove the parchment paper and weights, brush the crust with egg yolk, and bake for another 10 minutes, until lightly golden. Let cool slightly.

In a large bowl, combine the pumpkin puree, heavy cream, eggs, pumpkin pie spice, and sugar. Whisk until smooth and well combined.

Pour the filling into the partially baked pie crust and bake for 25–30 minutes.

While the pie is baking, combine the chopped pistachios, brown sugar, flour, and cinnamon in a bowl.

Add the butter and use your fingertips to rub it into the dry ingredients until a crumbly mixture forms.

After 25–30 minutes, carefully remove the pumpkin pie from the oven and distribute the pistachio crumble evenly over the filling.

Return the pie to the oven and bake for approximately 15 more minutes, until the crumble is golden brown and the pumpkin filling is set around the edges with a slight wobble in the center. If necessary, bake a little longer until the filling is properly set.

Allow the pie to cool completely before slicing and serving.