Separate tenderloin section from each chicken fillet. Place fillets between pieces of plastic, using meat mallet, gently pound fillets to an even thickness.

Place livers, the water, ginger, garlic, lemon grass, brown onion and peppercorns in large saucepan, stir over heat until mixture boils. Add chicken, reduce heat. Simmer, uncovered, about 5 minutes or until chicken is just tender, skim stock. Remove chicken from stock, slice thinly. Continue to simmer stock, uncovered, about 30 minutes or until reduced to about 1.5 litres (6 cups). Strain stock, discard liver mixture. Return stock to cleaned pan.

Meanwhile, place mushrooms in medium heatproof bowl. Cover with boiling water, stand 20 minutes. Drain mushrooms; reserve ⅓ cup (80ml) of the liquid. Discard stems, slice caps thinly. Add reserved mushroom liquid, sauce and noodles to stock in pan, simmer, uncovered, a few minutes or until noodles are soft. Stir in mushrooms, chicken and green onion. Just before serving, stir in coriander and sprouts.