1. Preheat the oven to 350°F (180°C). Line a baking sheet (13×15 inches /32x39cm) with a high rim with baking parchment or grease and dust with flour. Set aside.

 

2. Clean the rhubarb and remove the fibre on the outside. Cut into thin slices and mix with the raspberries in a large bowl. Mix the cornstarch and vanilla sugar, add to the bowl and mix well. Set aside.

 

3. Beat the butter with sugar and salt in a large bowl on high speed until light and fluffy. Add the eggs one after another and mix well after each addition. Add the vanilla extract and mix in. Mix the flour with cornstarch and baking powder, add together with the milk to the bowl and mix until just combined. Spread the batter on the baking sheet to get an even layer and spread the rhubarb raspberry mix on top. Sprinkle with brown sugar and sliced almonds and bake for 30-35 minutes or until a toothpick inserted into the cake comes out clean. Take out of the oven and let cool down. Dust with confectioners‘ sugar (optional) and serve with some vanilla ice cream or whipped cream.