Add ice cream, milk, black cocoa powder, maple syrup, vanilla to a blender and blend until it’s totally combined and there aren’t any lumps of ice cream. If it’s too thick, add more milk until it’s however thick you'd like. Taste and add more black cocoa, if desired. Note that the milkshake may look dark grey at the beginning, but gets very close to black the longer it sits.
2 cups (475 ml) vanilla ice cream, 1/4 to 1/2 cup (60 to 120 ml) milk, 3 tablespoons (26 grams) black cocoa powder, 2 tablespoons maple syrup, 2 teaspoons vanilla extract