Make the pie crust: In a large bowl, whisk together 2 cups all-purpose flour, 1 teaspoon salt, and 1 tablespoon sugar. Add 8 ounces of cold, cubed unsalted butter and cut it in using a pastry cutter or your fingertips until the mixture looks like coarse breadcrumbs with pea-sized pieces remaining. Sprinkle 6 to 8 tablespoons of ice water over the mixture, 1 tablespoon at a time, tossing gently with a fork until the dough just comes together. Checkpoint: The dough should hold together when squeezed but still look slightly shaggy.

Chill the dough: Form the dough into a flat disk, wrap it tightly in plastic wrap, and refrigerate for at least 30 minutes (or up to 2 days). This rests the gluten and makes rolling easier.

Preheat and prepare: Preheat your oven to 375°F. On a lightly floured surface, roll out the chilled dough into an 11-inch circle about 1/8 inch thick. Carefully transfer it to a 9-inch pie pan, letting the excess hang slightly over the edge.

Blind bake the crust: Prick the bottom and sides of the crust with a fork (this prevents large air pockets). Line the crust with parchment paper and fill with pie weights or dried beans. Bake for 12 to 15 minutes until the edges are light golden and the bottom is set and no longer wet-looking. Remove the weights and parchment. Checkpoint: The crust should feel firm and look dry on the bottom; it won't be fully cooked yet.

Cool the crust slightly: Remove the pie pan from the oven and set it on a wire rack to cool for 5 minutes while you prepare the filling.

Heat the cream mixture: In a medium saucepan, combine 1 cup heavy cream, 1/2 cup whole milk, and 1/3 cup malted milk powder. Heat over medium heat, stirring frequently, for 4 to 6 minutes until steaming and the malted powder is fully dissolved (no lumps visible). Do not boil; just bring to a gentle steam.

Combine with chocolate: Place 8 ounces of chopped semi-sweet chocolate and 4 ounces of chopped milk chocolate into a large heat-safe bowl. Pour the hot cream mixture slowly over the chocolate while whisking gently. Let it sit undisturbed for 1 minute to allow the heat to soften the chocolate, then whisk smooth until glossy and no streaks remain, about 1 to 2 minutes. Checkpoint: The filling should be silky, shiny, and completely smooth with no lumps.

Finish the filling: Stir in 1/4 cup unsalted butter (cut into small pieces), 1/4 teaspoon salt, and 1 teaspoon vanilla extract. Whisk until the butter is fully melted and incorporated. The filling should be warm and pourable.

Pour and set: Pour the warm chocolate-malt filling into the cooled pie crust, spreading it evenly with a spatula. The filling should reach just below the rim of the crust.

Chill thoroughly: Place the pie on a flat shelf in the refrigerator and chill for at least 4 hours, or preferably overnight (up to 24 hours), until the filling is completely set and no longer jiggles when you gently shake the pan. Checkpoint: The filling should be firm to the touch but still creamy inside; a knife should glide through smoothly without shattering.

Garnish: Just before serving, dust the top lightly with 2 tablespoons of malted milk powder and top with 2 ounces of chocolate shavings or curls. Serve chilled.