Wash the grapefruit then cut into quarters. Place in a pan, add salt and pour over the cold water. Bring to the boil, sieve and repeat twice (without the salt these times). Prepare the syrup by adding sugar and the litre of water in a pan. Add the grapefruit to the syrup and cook slowly for 3 hours. Leave to cool and keep in an airtight container.
To make the crumble, rub the butter into the flour until it resembles very coarse breadcrumbs. Do not rub it too much or the crumble will not be crunchy. Add the sugar to your breadcrumbs. Sprinkle the crumble on baking trays lined with baking paper and bake for 15 minutes at 180C. Leave to cool.
Using a blender, blend the sliced banana into a smooth puree. Mix the banana puree and the dulce de leche together in a bowl. Add the mixture to the top of the ganache and then sprinkle the crumble over the top.
Whip the cream and sugar together until it forms soft peaks.
Heat the ganache and pour into a glass of your choice. Add the banana caramel, then the crumble and finish with a dollop of Chantilly cream. Add 2 cubes of the chopped confit grapefruit (use only the skin for this) and top with a little grated chocolate.
For the confit grapefruit
2 pink grapefruit
cold water
500g caster sugar
1 litre of water
1 pinch of salt
For the ganache
1 pack of Gü After Noon Pots of Chocolate Ganache
For the crumble
180g flour
75g caster sugar
90g butter
For the banana and dulce de leche
1 banana
180g dulce de lechE
For the Chantilly cream
100g whipping cream
10g caster sugar