01 -
Combine flour, cocoa powder, powdered sugar, and salt in a bowl. Incorporate cold cubed butter using fingertips or a pastry cutter until mixture resembles coarse crumbs. Add egg yolk and gradually add cold milk, one tablespoon at a time, until a cohesive dough forms. Shape into a disc, wrap, and refrigerate for at least 30 minutes.
02 -
Preheat oven to 175°C. Roll chilled dough and fit into a 23 cm tart pan. Trim excess and prick base with a fork. Line with parchment and fill with pie weights or dried beans. Bake for 15 minutes, remove weights and parchment, then bake an additional 10 minutes. Cool completely before proceeding.
03 -
Heat heavy cream in a small saucepan until simmering. Pour over chopped dark chocolate and let sit for 2 minutes. Stir until smooth, then incorporate vanilla extract and salt. Pour ganache into cooled tart shell and refrigerate for 30 minutes until set.
04 -
Blend pistachios and whole milk until smooth. Transfer to saucepan, add heavy cream, sugar, and cornstarch. Cook over medium heat, stirring constantly, until thickened to custard consistency. Remove from heat, stir in almond extract if using. Cool for 5–10 minutes, then fold in one-third cup roasted pistachios. Spread evenly over ganache layer and refrigerate for 30 to 45 minutes.
05 -
Simmer heavy cream, then pour over chopped dark chocolate and butter. Stir until glossy and smooth. Pour over pistachio layer and level with a spatula.
06 -
Decorate edges with chopped or whole roasted pistachios. Refrigerate for at least 1 hour to allow all layers to set fully before slicing.