Press tofu for 30 minutes using a press or by placing it on a rack set over a baking sheet to catch the liquid, and then placing a heavy pan on it.
Combine soy sauce and oil in a shallow dish.
Cut tofu into bite-sized blocks (about 1 inch), add to soy sauce/oil mixture, and turn to coat all sides.
Preheat air fryer set at 375ºF for 5 minutes. Whe air fryer is preheated, toss tofu with cornstarch.
Add tofu to air fryer in a single layer. Cook 14 minutes, or until lightly browned, shaking basket halfway through cooking time.
Serve immediately, if desired. Fried tofu can be refrigerated for five days, or frozen for 3 months.
Make ahead tip: Press the tofu, covered, in the refrigerator up to 24 hours in advance. It will be all ready to air fry.
Add seasonings of your choice: salt and pepper, garlic or onion powder, taco seasoning, chili powder, or curry powder. How you season it will depend on what you're adding it to.
Substitute arrowroot for cornstarch if you want to make this tofu gluten-free.
Cooked tofu can be stored in the refrigerator, properly covered, for five days or in the freezer for three months.
To reheat, if you're planning on using the tofu in a stir fry, just toss it in near the end of the cooking time to reheat. If you're adding it to a salad or bowl, reheat it briefly (just a couple of minutes) in your air fryer, toaster oven, or skillet on the stove, or reheat the tofu in the microwave for just 10-15 seconds.
Don't overheat the tofu because it will become tough and chewy. (We determined this the hard way in one of our many tests of this recipe!)