Cube or tear tofu into pieces. Place in a large bowl and mix in soy sauce, garlic, and ginger.
Sift in cornstarch and toss to coat the tofu.
Drizzle oil over and toss again to coat.
Pan Fry: Add tofu chunks to a large skillet, keeping space between each piece. Heat over medium heat and cook 3-5 minutes on each side until golden brown.
Air Fry: 375°F for 10-15 minutes until golden and crispy.
Oven: Bake at 400°F on a parchment paper-lined baking sheet for 25 minutes, flipping the tofu halfway.
Transfer tofu to a plate and add the sauce to the skillet. Bring to a simmer, then stir constantly for 1-3 minutes until slightly thickened.
Add tofu and mix until all the tofu is coated in sauce. The sauce will thicken more as it cools.
For crispy sweet and sour tofu, add the tofu back to your air fryer or oven and bake another 3-5 minutes until crisp.
Garnish with green onions, toasted sesame seeds, or a drizzle of sesame oil if desired.
Notes
Tofu: You can also use extra firm tofu, but frozen tofu will have the best texture.To Freeze Tofu: Take the block of tofu out of its packaging, drain, and place into a freezer safe bag. OR, just freeze the tofu in its packaging -- note that this will result in more water inside the tofu, so you’ll have to press the tofu more. Freeze at least 3 hours but preferably overnight. Thaw in the fridge overnight or during the day, or quick defrost by thawing the tofu in a pot of boiling water.To Press Tofu: Wrap tofu in a paper towel or kitchen towel and place between two flat plates or cutting boards. Place a heavy object on top, such as a skillet or a heavy book. Let the tofu drain for at least 10 minutes. OR, you can forego the heavy object and just use your hands to press down on the plate with your bodyweight. Press slowly so you don't completely smash the tofu.