Wash and then trim the bottoms of the broccolini. Boil a small pot of water and steam broccolini in a bamboo steamer for approx 8 minutes, or until cooked but still with a bit of crunch. Meanwhile heat up oil and saute garlic and ginger until soft, add mushrooms and spring onion. Cook for 2-3 minutes and add oyster sauce. Coat the mushroom mixture well by stirring and let it bubble away for a short while. When the broccolini is done to your taste, pile it on top of the rice and top it off with the mushroom mixture.