Clean broccoli. Trim off flowers into bite-size pieces, lightly peel broccoli stalks and sliced into diagonal medallions. Heat wok on high add oil and when the oil is hot, add garlic and stir-fry 10 seconds. Add broccoli, stir-fry rapidly until the broccoli is covered in oil. When the wok is no longer oily, add a splash of water or chicken stock and continue to fry, stirring constantly for 3 minutes, replenishing water/chicken stock whenever wok becomes dry. Toss in mushrooms, stir, add oyster sauce, stir, cover and simmer at medium heat two minutes. Serve.