Set a large non-stick pan, skillet, or wok over high heat and add the oil.
Next, crumble the firm tofu with your hands or with a fork and transfer it into a non-stick pan. Cook and occasionally stir the tofu for about 10-15 minutes or so until some of the pieces begin to turn golden-brown.
Pour the seasoning and sauce mixture over the tofu and cook for another 10 minutes.
The Gravy
Reduce heat to medium. Pour the flour to the tofu sausage. Stir and cook for 5 minutes.
Next, slowly whisk in the water and soy milk and cook for about 5-7 minutes, until thick enough. Stir in vegan butter and salt + pepper to taste.