Various desserts made with rhubarb are traditional early summer treats in Finland. Rhubarb is used in pies, parfaits and sorbets or made into compote, kisel or juice. (See the note at the bottom of this page.)
Rhubarb is at its best in the spring, while its stalks are still young and tender and the leaves are not yet fully developed.
Very young and tender rhubarb stalks do not necessarily have to be peeled. The thicker peel of older stalks should be removed, as it has a tougher, woody consistency.
150 g (about 300 ml) flour
½ tsp baking powder
150 g butter
¾ dl water or cream
500 g fresh rhubarb stalks
150 ml sugar
1½ tbsp potato flour
Prepare the dough for the top crust of the pie. Mix the flour and the baking powder. Add the cold butter and rub the ingredients together using your fingers, until the mixture resembles breadcrumbs.
Pour in the liquid and rapidly stir it in, mixing as little as possible. If mixed for too long, the dough will become tough. Wrap the dough in plastic and place in refrigerator to harden for at least an hour.
To prepare the filling, mix the potato flour and the sugar. Rinse and lightly peel the rhubarb stalks. Cut the stalks into 2 - 3 centimetre long pieces. Spread a layer of rhubarb in a round pie pan. Sprinkle some sugar and potato flour mixture on top.
Continue filling the pan with alternate layers on rhubarb and the sugar-flour mixture. There should be a lot of filling, since it will sink considerably during baking. Increase the amount of it, if necessary.
Roll out the dough into a disk slightly wider than the pie pan. Raise the disk on top of the filling and push the edges to stick the sides of the pan and form a lid. Brush the lid with egg and prick it with a fork for the steam to escape from the filling during baking.
Bake the pie at 225 °C until the top has browned nicely, for about 35 minutes.
Let the pie cool slightly before cutting. Serve pie slices topped with whipped cream, creamy vanilla custard or ice cream.
Note: Rhubarb like most berries, some nuts, spinach, sorrel, beans, chocolate, cocoa, coffee and tea, among other items contains toxic oxalic acid. While the rhubarb stalks are safe to eat in moderate amount, the leaves must never be used in cooking. Oxalic acid binds vital nutrients such as calcium, inhibiting its absorption by the human body.
To weaken this effect, rhubarb is usually served together with some dairy product rich in calcium, like milk, cream or ice cream. This is a custom practised already among our ancestors, even though they never knew of the oxalic acid and its effects.
The acid in rhubarb may cause some dairy products to curdle when served together.
Recipe source: "Raparperitorttu", Sarje, I., ed. (1964) Hyvää ruokaa. Helsinki: Tammi.