Set the graham crust on a baking sheet for easy moving.
Whisk sugar, cocoa, cornstarch, and salt in a medium saucepan.
Slowly whisk in cold milk until smooth with no dry spots.
Cook over medium heat, whisking often, until thick and bubbling, 5–7 minutes.
Temper the yolks: whisk 1 cup hot pudding into yolks, then whisk yolk mixture back into the pot.
Simmer 1–2 minutes more, whisking, until glossy and very thick.
Remove from heat. Stir in chocolate chips, butter, and vanilla until fully melted and smooth.
Let stand 5 minutes, then scrape pudding into the crust and smooth the top.
Press plastic wrap directly on the surface. Chill until set, about 4 hours or overnight.
Top with whipped cream and chocolate shavings. Slice and serve cold.
Notes
Swap the graham crust for a baked pastry shell if you prefer. Try a pinch of espresso powder in the pudding to deepen the chocolate flavor. Store leftovers covered in the fridge for up to 3 days; add whipped topping just before serving for best texture.This recipe is an original creation inspired by classic Chocolate Pudding Pie Recipe flavors. All ingredient ratios and instructions are independently developed.