Combine the coriander seeds, black peppercorns, shallots, garlic, rock salt and sugar in a mortar and pound until a smooth paste is formed. Set aside.
In a bowl, lightly pound corn, then add in spice paste mixing until well combined. Add in Chinese leeks, then add in the rice flour and toss to coat evenly. Add in beaten egg and stir until well blended.
Drop by the spoonful into hot oil and fry until golden brown, about 2-3 minutes. Remove and drain well.