Make sure the tofu is completely thawed before using. Cut or tear tofu up into large chunks.
Mix together ginger, garlic, broth, soy sauce, sake, mirin, nutritional yeast, and sesame oil. Place in a wide dish.
Add the tofu and gently turn over to coat all sides.
Transfer tofu to a bowl (leave any excess marinade behind) and add flour. Gently toss to coat. Once the tofu is evenly coated with flour, sift potato starch over the tofu and toss again until evenly coated.
Air fry: Drizzle 1 tbsp oil over the tofu and toss well to coat. Place each tofu chunk into the air fryer. Make sure the tofu chunks are spaced apart and not touching. Air fry at 375°F for about 20 minutes or until browned and crispy. You may need to cook them in batches depending on how big your air fryer is.
Deep fry: Heat a pot or deep pan over high heat. Add enough oil to cover about an inch of the pot. Heat oil to 340°F/170°C. Fry tofu in batches until golden brown, turning every so often to make sure all the sides get fried. Transfer tofu to a wire rack to let excess oil drip off. For a crispier karaage, increase the oil heat to 350°F/180°C, then fry the tofu pieces again for 30-60 seconds until darker brown.
Serve tofu karaage with lemon wedges and a sprinkle of salt, if desired.
Notes
Twice Frozen Tofu: To double-freeze tofu, simply place the tofu (in the package is fine) in the freezer. Once frozen, place in the fridge to thaw for a day, then place back in the freezer overnight. Once frozen, transfer to the fridge to thaw again. You can also just freeze and thaw once, but the texture is better when twice frozen.Gluten-Free: Use gluten-free all purpose flour, rice flour, or all potato starch.