Combine the soy sauce, sugar, salt, cornstarch, and 1 Tbs. of cold water to dissolve everything. Reserve.
Soak the tree-ear mushrooms and the tiger-lily petals in just enough warmed water (not from the hot-water tap) for 45 minutes to an hour.
Heat 1/3 cup of vegetable oil in a wok or skillet until moderately hot, and pour in the beaten egg. Cook, whisking lightly, for 15-20 seconds. Pour the entire pan contents through a strainer, collecting the oil in a bowl. Set the strainer with the eggs aside to drain.
Return 1 Tbs. oil to the wok or skillet. Over the highest heat you can get, stir-fry the pork strips for about one minute, until browned on the outside. Remove and reserve.
Wipe the wok out, leaving a light film of oil. Strain out the mushrooms and tiger lily petals, shaking most but not all of the water out. Add to the pan and cook for two or three seconds. Add the chicken stock and the soy sauce mixture from step 1. Bring to a boil and cook for three minutes, until the sauce thickens.
Return the pork strips and the egg curdles back to the wok and stir into the mixture. Cook for another 30 seconds or so, then spoon onto serving plate.
Serve with flour tortillas or Chinese thin pancakes, with hoisin sauce and snipped green onions.