A popular dish in Korean Buddhist temple cuisine.
Combine the ketchup, syrup, and gochujang in a large pan over medium heat. Cook, stirring, until bubbling. Remove from heat.
Evenly coat the tofu in the potato starch.
Heat the oil in a separate large, heavy skillet until 335.F.
Lower the heat to medium. Add the tofu to the oil and fry until the bottoms are light brown and crispy.
Flip the tofu and continue frying until golden and crispy on the other side. Remove tofu from the oil.
Reheat the oil to 340.F.
Transfer the tofu back to the oil and re-fry, rotating frequently, until all sides are golden brown and crunchy.
Transfer tofu from oil and let drain.
Bring the prepared sauce back to a simmer, add the tofu, and gently mix to coat. Serve immediately.