You have never had such a great rhubarb crumble – and Wellington’s Billie Lusk, as a very busy caterer to the stars, says this is the most requested recipe! I added a little orange zest to the rhubarb, and please note the variances in the sugar: if, like me, you are not a sweet-tooth person, go with the lower amount; if you prefer your rhubarb sweeter, go with the amount in the original recipe.