In the bowl of a stand mixer fitted with the paddle attachment, combine flour, sugar, salt, and cold butter. Mix on low until no visible butter pieces remain and the mixture resembles fine sand.

Whisk the whole egg and yolk together until fully combined. Add to the mixer and mix on low just until a smooth dough forms. Divide into two equal portions (approximately 275 g each), flatten into discs, wrap tightly, and refrigerate at least 2 hours or overnight.

Roll out one disc, line a 9-inch pie pan, and refrigerate until firm.

Preheat the oven to 350°F convection or 375°F conventional. Line the chilled shell with crumpled parchment and fill with baking weights. Bake 10 minutes until the sides and bottom look matte. Remove the parchment and weights and bake another 5 minutes until the bottom just begins to color.

Reduce the oven to 350°F conventional. Whisk together the sugar, cocoa, and salt in a bowl. In a separate large bowl, beat the eggs, melted butter, evaporated milk, vanilla, and coffee extract. Add the sugar mixture and whisk until smooth with no lumps.

Pour the filling into the parbaked shell. Bake at 350°F for 20 minutes, then reduce to 325°F and continue baking 25 to 40 minutes more, until the edges are set and puffed and the center is no longer liquid. Total bake time is 45 to 60 minutes.

Cool completely at room temperature before slicing, at least 2 hours. Serve at room temperature or cold.