Clean and wash the rhubarb, drain well and cut into thick slices. Mix with 1 tablespoon of sugar
Cream fat and 125 g sugar, vanillin sugar, lemon peel and salt, separate 3 eggs and chill the egg white. Stir in 1 egg and the egg yolks one after the other, alternating with 20 g cornflour. Mix flour, 80 g starch and baking powder, stir in briefly together with the milk
Grease a springform pan (26 cm Ø) and dust with flour. Put about 2/3 of the dough into the form, smooth it down and spread the rhubarb on top. Spread the rest of the dough as small blobs on the rhubarb and spread it lightly. Bake in the preheated oven, 2nd shelf from below (electric oven: 200 °C/ convection oven: 175 °C/ gas: level 3) for 25-35 minutes
Beat the egg white until stiff, add 150 sugar and beat for another 2-3 minutes. Finally, briefly fold in lemon juice. Remove the cake from the oven and turn down the temperature (electric cooker: 175 °C/ circulating air: 150 °C/ gas: level 2). Spread the meringue cloudy over the cake so that a 1 cm wide edge remains free all around. Bake the cake on the same rack for another 25-30 minutes. Remove the finished cake from the edge of the mould with a damp knife and let it cool in the mould on a cake rack