Heat the milk, cream and chili to approximately 90° C and pour it over half of the chocolate in order to emulsify. Add the rest of the chocolate and heat to 85° C to pasteurise.
Cool the chocolate milk quickly in the freezer to between 0 and 3° C.
Meanwhile, make the mango purée using ripe mangos. Peel the mangoes, remove the stones and blend until smooth. Withhold 4 teaspoons of purée.
Mix the cold chocolate milk with the mango purée. Place one spoonful of mango purée in the bottom of each glass then carefully pour in the chocolate milk.