Peel 1El shavings from the chocolate with a peeler and place in the refrigerator. Roughly chop the remaining chocolate.

Pour 2,400 milk in a saucepan, rub the peel of half a grapefruit over the saucepan, bring to the boil. Pudding powder (stir until until 2 teaspoons and 100 ml milk until smooth). Stir into the boiling milk and bring to the boil again. Remove the saucepan from the stove and dissolve the chopped chocolate while stirring and let it cool down to lukewarm.

Whip the cream until stiff. Stir one third of the cream into the pudding, fold in the rest. Pour the white chocolate pudding into 4 glasses and refrigerate for 2 hours.

Peel the grapefruit so that the white skin is completely removed. Cut out the fillets between the separating skins, catching the dripping juice.

Fill up the drained juice with water to 150 ml, bring to the boil with sugar and lemon juice. Stir the remaining custard powder in a little water until smooth, stir into the boiling juice and bring to the boil again.

Spread the grapefruit compote on the glasses and serve sprinkled with chocolate chips.