Preparation Steps

• If your crust isn’t already baked, blind-bake a 9-inch deep-dish shell according to package or recipe directions and let it cool completely on a rack.
• Set aside 1/2 cup of the milk in a measuring cup. In a medium saucepan, warm the remaining 2 1/2 cups milk with the espresso powder and 1/4 teaspoon sea salt over medium heat until steaming but not boiling.
• In a separate bowl, whisk together the sugar, flour, and cocoa. Pour the reserved 1/2 cup cold milk into this dry mixture and whisk until perfectly smooth (no dry pockets).
• Slowly stream the hot milk into the cocoa mixture while whisking constantly, then return it all to the saucepan. Cook over medium-low heat, stirring and scraping the corners of the pan with a heatproof spatula, until thick and gently bubbling, 8 to 12 minutes. Keep it at a low simmer for 1 minute to fully activate the thickener.
• Remove from heat and add the chopped dark chocolate. Stir until completely melted and smooth; if needed, set over the lowest heat for 30 to 60 seconds, stirring, to finish melting. Off the heat, stir in the butter and vanilla until glossy and silky.
• Place a fine-mesh sieve over the cooled pie crust and pour the warm filling directly through the sieve into the shell. Smooth the top, tap the pie gently on the counter to release air bubbles, then press plastic wrap directly onto the surface of the custard.
• Chill until fully set, 4 to 6 hours (or overnight). The surface should no longer wobble in the center when nudged.
• Just before serving, whip the cream on medium speed to soft peaks. Rain in the powdered sugar, add the vanilla and a pinch of salt, then continue whipping to medium-firm peaks.
• Uncover the pie and mound or pipe the whipped cream on top. Make chocolate curls by running a vegetable peeler along the long edge of a room-temperature chocolate bar and scatter over the cream. Slice and serve.