Mix the sauce ingredients together in a medium bowl.
Add the slurry ingredients into a small bowl and stir to mix well.
In a high-walled skillet or pot, heat the oil to 375°F (190°C). Carefully add the tofu. Fry until both sides turn golden, about 3 minutes. Flip once or twice to ensure even cooking. Remove the tofu from the oil and transfer it to a big plate.
Pour off all but 1 tablespoon of oil from the pan (alternatively, you can heat 1 tablespoon of oil in another large skillet).
Add the garlic, ginger, green onion (white part), and doubanjiang to the pan. Turn the heat to medium. Stir fry to release the fragrance until the oil turns red, about 2 minutes.
Add the fried tofu, carrots, bell peppers, and bamboo. Stir fry for 30 seconds to 1 minute.
Pour in the sauce. Bring to a boil then reduce to a simmer, gently flipping occasionally. Simmer for 5 minutes.
Add the green onion (green part). Mix the slurry again so the cornstarch is fully dissolved. Pour in the slurry and mix with a spatula until the sauce thickens.
Drizzle in a teaspoon of sesame oil to finish up.
Serve hot over steamed rice as a main dish.
Be careful that you are not buying silken tofu. Some brands carry soft tofu (e.g. House Foods), that are too smooth and will not develop the desired texture.
If you do not wish to make the dish vegan, you can use regular oyster sauce instead.