Heat a wok or skillet. Add 1 tb vegetable oil. Add thinly sliced beef and sautee until half cooked. Combine soy, hoisin, garlic, sugar, chili, lemon and cornstarch into sauce and add to beef. When glazey, about 1 minute, add salt & white pepper to taste and stir in vegetables. Stir-fry until mushrooms and snow peas are cooked but still crunchy. Serve immediately with plain rice.