Drain the tofu and cut into bite-sized cubes. Pat dry with a paper towel until there is as little moisture on them as possible.
Put 3-4 tbsp of corn starch into a large bowl and toss tofu cubes into it until they are lightly coated. This allows the tofu to get crispy (rather than mushy) when you go to fry it.
Measure the oil into a large fry pan on medium heat and fry the tofu cubes until browned, flipping every few minutes. This should take approximately 10 minutes.
Spoon the tofu cubes back in the large bowl, and place them off to the side.
With the remaining oil in the pan, pan-fry the broccoli florets until they start to crispy. About 7-10 minutes.
While the broccoli florets are cooking, mix together the water and cornstarch in a small bowl, until combined. Then add the remaining sauce ingredients.
When the broccoli is done, stir in 3/4 of the sauce on low heat. Once mixed, remove from the heat immediately. Place broccoli in another large bowl.
Place tofu back into the fry pan on low heat and add the remainder of the sauce. Again, once mixed, remove from the heat.
Portion both broccoli and tofu into serving bowls and top with sesame seeds and green onion.