175 g butter
150 g sugar
6 tsp vanilla sugar
1 knifetip salt
3 egg yokes
250 g flour
2½ tsp baking powder
80-90 ml milk
3 egg whites
200 g sugar
100 g hazelnut kernels (walnut kernels or almonds are also good)
½ kg rhubarb
Rinse and wipe the rhubarb dry. Cut in 1-2 cm pieces.
Chop the nuts (or almonds) in not too small pieces.
Stir the butter creamy with sugar, vanilla sugar, salt and egg yokes. Mix flour with baking powder and add it bit by bit to the butter cream with the milk.
Grease the baking pan (24x30x5 cm) with butter and sprinkle with dry breadcrumbs. Put the dough in the baking pan, making the suface smooth.
Turn on the oven (200 ºC).
Whip the egg whites almost stiff, add the sugar at 2-3 times and whip stiff again. Gently stir with rhubarb and nuts. Spread it evenly on the dough, and bake in the middle of the oven 40-45 minutes.
Serve as it is, or with whipped cream or creme fraiche.
If you can't get hold on rhubarb, try with cranberries and tart apples cut in small pieces (even measures), see this link