Prepare the Biscuits: Crush biscuits into small pieces by placing them in a bag and rolling over them with a rolling pin or pulsing them in a food processor until coarse crumbs form.

Mix Dry Ingredients: In a bowl, combine crushed biscuits with cocoa powder, mixing until cocoa is evenly distributed through the crumbs.

Combine Milk and Sugar: Pour milk into a saucepan, add sugar, and heat over medium heat, stirring constantly until sugar is dissolved.

Thicken the Mixture: Sprinkle cornstarch into the milk and sugar mixture, whisking constantly to prevent lumps. Keep cooking on medium heat, stirring until mixture thickens like pudding.

Combine and Chill: Add thickened milk mixture to the bowl with biscuit and cocoa mixture. Stir until well combined. Pour into a serving dish or individual cups.

Refrigerate: Chill pudding in the refrigerator for at least 2 hours or until set.

Serve: Once chilled and set, serve chocolate biscuit pudding as is or with whipped cream or a sprinkle of cocoa powder for extra flavor.