Put the flour in a bowl, make a well in the middle, dissolve the yeast in a little milk, pour into the recess, cover with a little flour and let the dough rise for about 15 minutes. Then add the remaining dough ingredients and knead everything well. Let rise for 30 minutes.
Mix the rhubarb with 50 g sugar and flour. Roll out the dough on a baking sheet lined with baking paper and let rise for another 15 minutes.
Mix the crème fraîche with 100 g sugar, the custard powder, the egg and the vanilla pulp. Spread the rhubarb on the dough and spread the mixture on top. Bake in the oven preheated to 175 ° for about 30 minutes.
After about 15 minutes of baking, spread the almond flakes on the cake.