Heat 1 cup of cooking oil in a small pot. Once hot, carefully add the cubed tofu. Fry until golden brown on all sides, then set aside. The crispy exterior holds up well in the stir-fry while keeping the tofu soft inside.
In a wok, heat 3 tablespoons of the oil used for frying. Sauté the onion and garlic until fragrant and the onion softens. Add mushrooms and carrot slices, tossing them for about 2 minutes to combine flavors.
Pour in 2 tablespoons of soy sauce, then mix in snow peas, the chicken cube, and 1 cup of water. Bring to a gentle boil, allowing the vegetables to absorb the savory flavors.
Add sliced cabbage, bok choy, and green peas. Stir everything together and cover for 3 minutes. This ensures the greens are tender but still maintain a slight crunch.
Gently fold the fried tofu into the vegetables. Sprinkle ½ teaspoon of sugar, and season with salt and black pepper. The tofu absorbs the sauce, making each bite flavorful.
Mix 1 tablespoon of cornstarch with 3 tablespoons of water. Pour into the wok and stir continuously until the sauce reaches your desired thickness. Finish with 2 teaspoons of sesame oil for aroma.