Open the tin, remove the buttermilk roll and cut it in half lengthwise. Place the lower halves in a greased, ovenproof dish. Place 5 raspberries on each half. Wash the basil, dab dry and cut the leaves from a stalk into fine strips. Mix 2 tablespoons of sugar and vanillin sugar. Sprinkle basil and sugar mix on the raspberries, cover with the other half of the roll and press lightly.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 25-30 minutes. Stir the sauce powder, 4 tablespoons of milk and 2 tablespoons of sugar until smooth. Bring 460 ml milk to the boil and stir in the powder. Bring the sauce to the boil again while stirring and set aside. After about 20 minutes, pour the vanilla sauce over the cookies and bake until done. Remove the cookies from the oven and decorate with basil leaves and icing sugar