1.Heat oil in a large frying pan over medium heat; cook mushrooms, onion and ginger over high heat, stirring, until mushrooms are soft. Add sauce; cook until evaporated.Remove from heat; stir in rind and water chestnuts. Cool.
2.Working in batches, place wrappers on a board. Place 2 level teaspoons of mushroom mixture in the centre of each wrapper. Brush a little water around the edges of each wrapper; bring four corners in to the centre, then press edges together to seal.
3.Line a bamboo steamer with baking paper; place wontons in steamer. Place steamer over a wok or large saucepan of simmering water; cover, steam wontons 5 minutes or until heated through.
4.Meanwhile, make warm dipping sauce.
5.Serve wontons with dipping sauce.
Woodear mushrooms are a type of Asian mushroom. They are available from Asian food stores and specialty greengrocers. The wontons can be made several hours ahead; keep refrigerated in a single layer on a tray, without touching.Note