For the shells (top hats): Sift plain flour and rice flour together. Place sifted dry ingredients and salt into a mixing bowl. Add egg and mix with water to make a runny batter. Strain the batter.
Heat oil in a deep wok or pan. Place pie tee mould in the hot oil for one minute. Remove the hot mould and dip into the batter.
Put mould in hot oil until shell is golden in colour. Give the mould a little shake to dislodge the shell. Pick it up with a pair of chopsticks and place on absorbent paper to cool. Store in an airtight container or tin until needed.
For the filling: Heat oil and lightly brown ginger. Add mushrooms, yambean and carrot and stir-fry for a while. Add seasoning and simmer until quite dry. Dish up and cool.
Just before serving, put in two teaspoons of filling and garnish with shallot crisps. Serve with chilli sauce.