Preheat oven to 180c. Prepare baking try (20x21, 7cm deep) by greasing it with butter and dust with flour
Place in a bowl melted and cooled down butter with sugar and eggs. Bit together with whisk until combined. Add both types of flour and baking powder to the mix. Mix it all together until all ingredients combine. You don’t need to do it for too long
Place the cake into the baking tray spreading evenly. Add roughly chopped rhubarb on top. Remember to peel the rhubarb before choping it into pieces.
Bake for around 40 min or until the cake is done
Decorate with icing sugar. You can enjoy it hot as well as cooled down