Roast the almond slivers in a dry pan until golden brown, let them cool down. Stir the jelly powder into 1/2 litre of cold water and let it swell for 5 minutes. Add sugar and heat while stirring until the sugar has dissolved (do not boil).
Pour the almonds into 4 glasses. Pour raspberry jelly on top. Put in a cool place for about 3 hours. Whisk milk and sauce powder vigorously for about 1 minute with the whisk of the hand mixer. Decorate dessert with banana slices and mint.
Serve with vanilla sauce.