Boil grated radish in a saucepan of water for five or six minutes. Drain. Place boiled radish in a saucepan, add ingredients (A) and cook gently over a low heat until the radish turns soft and almost all the liquid has dried.
Mix rice flour, sago flour, salt and water together into a batter and leave aside. Fry the sliced shallots until crispy. Dish out and set aside crush when cool. Use the remaining shallot oil to stir-fry the chopped dried prawns until fragrant.
Combine rice batter, shallot crisps and dried prawns with the radish mixture, then cook over a low heat until mixture turns into a thick paste or is half cooked.
Pour mixture into a greased 20cm square cake tin. Smoothen the surface and steam over rapidly boiling water for an hour or until cake shrinks away from the sides of the tin. Leave to cool thoroughly, then cut into 1cm-thick slices. Serve with chilli sauce.