Arrange two or three glazed pieces of strawberry on top and sit the top half of the sponge on top. Dust with icing sugar to serve. Prepare ahead: The cake on its own, without the filling ...

Sieve over remaining flour, add 1 tbsp hot water and fold gently to combine. Spoon sponge equally over the rhubarb, then bake until golden and cake springs back when lightly pressed (15-20 minutes).