Mix the water and sugar until the sugar has dissolved. Stir in the lime juice and fish sauce, set aside.
Mix the flour with all the other ingredients up to and including the oil, mix in the onions. Cover the batter and leave to stand for approx. 20 mins.
Heat the oil in a non-stick frying pan. Sauté the shallots and carrots for approx. 3 mins., add the mushrooms and cook briefly. Add the fish sauce.
To prepare the pancakes
Heat a dash of oil in a non-stick frying pan. Pour 1/8 of the batter into the pan, reduce the heat. Fry for approx. 6 mins. until the underside is cooked, spread some of the filling and sprouts on one side, carefully fold the empty side over the top, cook the pancake for a further 2 mins. Make seven more pancakes using the remainder of the batter and filling. Serve with the dip and spring onions.