When I was younger, a cluster of rhubarb grew in our garden in Sweden. The stalks were firm, with flushes of pink, at the start of the summer and I was always fascinated by this plant with its huge lily pad-like leaves and edible stems. We baked it, doused in sugar, in simple pie crusts to eat with vanilla whipped cream. This recipe takes things a little further, with almonds for crunch and a wholemeal crust for extra nuttiness. The filling will be pretty wet once cooked so I recommend cooling it completely to allow it to set fully.