Combine both flours in a mixing bowl; add the egg, water and salt to form a batter. Whisk slowly until well mixed. Strain batter.
Heat oil in a saucepan, with the pie tee mould immersed in the oil until mould is just hot. Lower the heat. Dip hot mould in the batter, ensuring that it´s thoroughly coated. Allow excess batter to drip off, then plunge mould into the hot oil. (the mould should not be overly hot and the batter must not sizzle when the mould is immersed.)
To separate the batter from the mould, jiggle the mould up and down to loosen the soft edges around it. The batter should come loose with a slight shake. Allow the casing to cook until it´s light brown. Drain. Cool and store in an airtight container.
For the filling, fry garlic and prawns until fragrant. Add turnip, carrot and seasoning. Cook for six to seven minutes and simmer until vegetables turn soft. Remove to cool. Put a little of the filling in the pie tee cases. Garnish and serve immediately.