Clean and trim the rhubarb to fit into a baking dish, add the raisins and the orange juice.

Cover with foil and bake for 30-40 minutes until the rhubarb is soft, and the raisins have soaked up the juice and become swollen

Roll out the puff pastry until it is a little smaller than a baking sheet. Grease the sheet well before laying the pastry out on it. Score the pastry with a sharp knife, an inch in from the edge all the way around, making sure you don't cut right through. Stab repeatedly inside this score line with a fork.

Bake for around 25-20 minutes, until the outside ring has puffed up, and is looking lightly golden.

Remove the pastry from the oven, and lay out the rhubarb slices in the middle, topping with the swollen raisins.

Pour the orange juice mixture into a small pan, bring to the boil, and add the cornflour until it resembles a thick syrup. Pour the syrup over the fruit, keeping it within the outer ring. Let cool.

Mix the icing sugar with a little cold water and drizzle over the entire dessert before serving.