Pull or prepare 2 ounces of fresh espresso into a small heat-safe bowl or measuring cup; if using instant espresso powder, mix 1 tablespoon powder with 2 tablespoons hot water until dissolved.

Add 1.5 tablespoons unsweetened cocoa powder, 1 tablespoon granulated sugar, and a pinch of salt to the hot espresso; stir with a whisk or fork for about 30 seconds until a smooth paste forms.

Pour in 2 tablespoons hot water and whisk vigorously for 30 to 45 seconds until the mixture is silky, shiny, and slightly lighter in color.

Fill a tall glass three-quarters full with ice cubes to keep the drink cold and prevent dilution.

Carefully pour the warm chocolate espresso mixture over the ice, allowing it to chill the brew and create a gradient effect.

Slowly pour 6 ounces of cold milk alongside a long spoon or straw to maintain a layered look until the glass is nearly full.

Stir thoroughly with a long spoon or straw for 20 to 30 seconds until the chocolate, espresso, and milk are fully combined and uniform in color.

Taste and adjust sweetness or coffee strength by adding more sugar or espresso as needed, then top with whipped cream if desired.