Combine rice flour, water and salt in a large mixing bowl. Leave aside for 10-15 minutes.
Heat 2 tablespoons oil in a non-stick wok or saucepan. Add dried prawns and fry until fragrant. Add mushrooms, pumpkin and the seasoning ingredients. Fry for 1-2 minutes.
Add the rice flour batter and continue to cook over a low heat until it forms a smooth paste.
Grease a 28cm square or round pan. Add about 100-125ml water into the non-stick wok or saucepan and mix well. Then pour the contents into the cake pan. Stir well to mix evenly then level the surface with a spatula. Put the pan into a steamer and steam over rapidly boiling water for 1-1¼ hours.
Remove the pan and leave aside to cool completely.
Sprinkle some chopped spring onions, red chilli and shallot crisps. Slice into serving pieces and serve with chilli sauce.