Cook rhubarb with sugar, lemon juice and water then strain through muslin to remove the majority of the juice. Leave the puree to go cold.

Jelly:

Soak 3 leaves of gelatine in cold water till soft. Stir into the juice.

Cling film 8 rings as tightly as possible and turn them cling film side down on a tray. Spoon a little jelly into each mould to about 1cm deep and leave to set.

Soak the remaining gelatine leaves in cold water, once soft gently melt them without letting them get too warm. Once the rhubarb puree is cold fold in the soft gelatine then lightly fold in the whipped cream. Spoon this onto the set jelly in the rings and smooth off the top. Refrigerate to set

For the toffee sauce put the sugar in a heavy based saucepan with a little water. Bring to the boil and simmer till just turning into caramel. Remove from the heat, allow it to cool for a minute then pour in 75ml cold water. Swirl the pan to mix in well and leave to go cold.

Cut the pineapple into chunks about 3cm chunks. Heat a non stick frying pan and roast the chinks on each side till nicely browned.

Turn the mousses on to the serving plates jelly side up and carefully remove the cling film. Using a blow torch or a warm cloth just slightly heat the outside of the rings so they slide off easily.

Put 2 tablespoons of the caramel into a pan with the milk and warm through, but do not boil.

Mix the sesame seeds into the remaining caramel and pour onto the plates and place the pineapple chinks on this. Using a hand blender whizz the milk and toffee mixture to a foam and spoon on the plates and serve.