Place the cubed tofu in a medium bowl and drizzle the soy sauce over the top. Using a silicone or wooden spoon, gently mix to evenly coat the tofu while maintaining its delicate texture. Set aside to allow the flavors to absorb.

In a separate medium bowl, combine the cornstarch, garlic powder, and black pepper. Stir well with a fork to ensure even distribution of the dry ingredients.

While the tofu marinates, preheat a large ceramic non-stick skillet over medium heat. Add half of the olive oil, ensuring it reaches a temperature hot enough to create an immediate sizzle upon contact with the tofu.

Transfer the marinated tofu cubes into the bowl with the cornstarch mixture. Stir gently until each piece is evenly coated, forming a slightly sticky layer that will crisp up beautifully when cooked.

Working in batches, arrange half of the tofu cubes in a single layer in the hot skillet. Allow them to cook undisturbed for 2–3 minutes until golden brown. Flip each piece carefully with a spatula and continue pan-frying for another few minutes until all sides are crispy. If desired, pour in half of the reserved marinade from the bowl to enhance flavor. Once cooked, transfer the tofu to a plate and repeat the process with the remaining batch, adding more oil if necessary.

Sprinkle with sesame seeds and freshly chopped green onions for a vibrant garnish. For the best texture, serve immediately, as the crispiness diminishes over time.