heat oil in a non-stick pan at medium heat. break tofu into pieces and generously coat with cornstarch. once oil is hot, add tofu and fry until golden and crispy, about 7-10 mins each side. while tofu is frying, combine all ingredients for sauce and heat in separate pan at medium heat until it starts to thicken. once tofu is cooked, transfer into sauce and toss pieces until evenly coated.