Stir the jelly powder into 1/4 litre of cold water and let it swell for 5 minutes. Add 2 tablespoons of sugar and dissolve over a mild heat (do not boil). Pour into glasses and chill.
Mix cream, sauce powder and remaining sugar. Bring milk to the boil. Remove from heat. Stir in the sauce powder and bring to the boil again. Roast almond slivers in a pan without fat until golden brown.
Let it cool down. Pour vanilla sauce on the jelly and sprinkle with almond slivers.