Mix all the ingredients for the sweet and sour sauce in a bowl. Set aside.

Heat 1/4 cup water in a large nonstick skillet over medium-high heat until boiling. Spread broccoli and cook covered for 1 minute, or until it reaches the desired texture. Transfer the broccoli to a plate and wipe the extra water from the skillet with a few paper towels held in a pair of tongs.

Heat a tablespoon of oil (more oil if using a carbon steel or a cast iron pan, to prevent sticking) in the same skillet over medium-high heat. When the oil is hot, carefully spread the tofu in the skillet. Cook the tofu without disturbing it until the bottom side turns golden brown, about 5 minutes. Flip tofu with a spatula and grill the other side to the same doneness. Transfer the tofu to a plate and set aside.

Add a tablespoon of oil into the same skillet and heat on medium-high heat. Add onion. Stir and cook for 2 minutes, until the edge of the onion turns slightly golden.

Add the garlic and ginger. Stir a few times until fragrant.

Add the sweet and sour sauce. Add the cooked tofu back into the skillet. Stir gently to mix well with the sauce. Cook until the sauce has reduced to the desired thickness, another 2 to 3 minutes.

In a large bowl, add the cooked broccoli. Pour the tofu and all the sauce on top. Serve with steamed rice or noodles on the side.