Yin Yang Tofu

Tofu is a relatively young ingredient in my repertoire. It has only been 10 years since I had started using this in my dishes. Whenever I come across a new recipe for tofu that I think will suit our tastes, I gives it a try.
This is a variation of the recipe that I got from Martin Yan's Invitation to Chinese Cooking. I substituted some of the ingredients with what I had in my pantry. It turned out true to its name - one half soft and sweet and the other robust and spicy. It was indeed a harmony of flavors, colors and textures.
Serves 6
Ingredients:
For Yin sauce:
1/3 cup vegetable stock
3 tbs oyster  flavored sauce (vegetarian)
2 tsp sesame oil
1/4 tsp pepper

For Yin Tofu:
1 tbs cooking oil
14 oz. firm tofu, drained and cut into 1/2" cubes
5 oz. spinach (or you can use button mushrooms, sliced)

For Yang Sauce:
3 tbs white vinegar
2 tbs tomato  ketchup
1 tsp soy paste
1/2 tsp chilli-garlic sauce
1/2 tsp sugar

For Yang tofu:
1 tbs cooking oil
14 oz. soft tofu, drained an cut into 1/2" cubes
5 oz. spinach (or you can use 2 oz. frozen peas and 1/4 cup water chestnuts, sliced)

Method:
Combine the ingredients for the yin and yang  sauces in separate bowls. Place a wok over high heat. Add 1 tbs of oil, coat all sides of the wok. Add firm tofu, spianach and the yin sauce; bring to a boil. Reduce the heat, cover and simmer for 2 minutes. (If you are using mushrooms, water might come out when cooking, in which case add 1 tsp corn starch mixed with 1 tbs water to make the sauce thick.)
Once the sauce thickens, place it on one side of the serving platter.
Clean the wok and place it over high heat; add 1 tbs oil and coat all sides of wok. Add the soft tofu, spinach and the yang sauce. Repeat the process just as in the case of yin tofu. Place the prepared tofu on the other side of the platter and serve.