Grease the baking sheet. Prepare the rhubarb and cut into pieces. Separate eggs and place egg whites in a fat-free mixing bowl. Beat the fat, 150 g sugar, vanilla sugar and salt until frothy. Stir in the egg yolks one at a time. Work in the flour and baking powder in portions, alternating with the milk. Use a spatula to deepen the fairly firm dough on the baking sheet. Beat the egg white and a pinch of salt until stiff, while beating in 200 g sugar. Keep beating until the sugar is dissolved. Fold in the almonds and rhubarb and spread the meringue mixture on the dough. Bake at 200 ° C for about 30-35 minutes.