Cut the rhubarb into desired pieces and masserate with some sugar over night.
Cut the butter in 1.5cm dice and place in a bowl with the rest of the Crumble mix ingredients. With the help of a wooden spoon mix until you obtain larges grains.
Peel & core the apples and cut in large dice, reserve.
In a bowl whisk together the cream, the 60gr of sugar, egg and the poire william.
Split the vanilla beans and put the seeds in the mix.
In an oven tray place the apple and rhubarb in the bottom, pour over the fruits and cook in the oven for 10 minutes at 180ºc .
Pull the dish out of the oven and place the crumble mix over the fruit and cook in the oven for another 20 to 25 minutes.
To serve with vanilla ice cream.