Wash the rhubarb the night before, peel, cut into pieces, sprinkle with sugar and leave to stand overnight.
On the baking day, knead a shortcrust pastry from the dough ingredients and wrap it in cling film in the refrigerator for 1 hour.
Preheat the oven to 200 ° C. Pour off the drawn water from the rhubarb.
Grease the tart pan, roll out the dough and place in the pan, pressing up one edge. Prick the bottom several times with a fork and spread the rhubarb on top.
Mix an egg cream from the cream ingredients. Place on the rhubarb and bake the tart for about 30 minutes.
In the meantime, beat the egg whites for the meringue until stiff, only then gradually add the sifted powdered sugar and continue beating until the mixture has a creamy sheen.
Lower the baking temperature to 130 ° C, spread the meringue on the tart and let it dry in the oven at 130 ° C for about 1 hour until it is slightly browned on the surface.