Tofu with black bean sauce

2 tablespoons oil
3 cloves garlic, minced
2 quarter-sized pieces of ginger, minced
1 teaspoon fermented black beans.1 tablespoon black bean sauce
1 cup vegetable stock or water
2 blocks firm fried tofu, in 3/4 inch cubes
1 tablespoon sesame oil1 tbs cornstarch Heat oil in large skillet or wok. Add the ginger and garlic; saute for about 20 seconds . Add the black beans and the green onion and saute for about 10 seconds. Stir in the black bean paste and vegetable stock; mix well. Then add the tofu cubes. Turn the heat down to maintain a strong simmer; cover and let cook about 20 minutes. Add the cornstarch with water mixture until thickened and at last add sesame oil .