Heat 1 cup stock in a non stick wok. Heat 2 tbsps oil in another non stick wok.
Cut both the bean curd into small cubes and keep them separately. Add garlic to the wok with oil. Add oyster sauce to the wok with vegetable stock and mix well.
Sauté garlic till lightly browned. Add tomato ketchup, red chilli sauce and mix. Add firm bean curd cubes and mix.
Mix cornflour with 2 tbsps water and add 1 tbsp of this mixture to the wok with firm bean curd and cook till the sauce thickens
Add the silken bean curd to the pan with the stock and mix. Add the remaining cornflour mixture and mix. Add salt and mix gently. Add a little more tomato ketchup and salt to the other wok and mix.
Finely slice spring onion stems and greens and keep them separately. Transfer the two bean curd mixtures into two separate compartments of a yin yan serving bowl. Add the spring stems to the part with silken bean curd and the greens to the part with firm bean curd. Serve hot.