14 ounces to 1 pound medium-firm or firm tofu, patted dry with a kitchen towel
1/4 cup potato starch (may substitute cornstarch)
2 cups vegetable oil
1/4 cup ketchup
1/4 cup Korean rice syrup (may substitute 3 tablespoons sugar or honey)
3 tablespoons gochujang (Korean chile paste)
1 tablespoon toasted pumpkin seeds
Cooked white rice, for serving
Cut the tofu into 1-inch dice and put the pieces in a zip-top bag. Add the potato starch, seal the bag and gently turn the bag over until the tofu is well coated. Remove each piece from the bag individually (to keep them from sticking together) and transfer to a large plate lined with plastic wrap, parchment paper or a silicone baking mat, leaving space between the pieces.
Set a cooling rack over a large rimmed baking sheet.
In a large, deep skillet or Dutch oven over medium-high heat, heat the oil to 340 degrees. Carefully add the tofu pieces, one at a time, making sure they don’t touch. (Work in batches if necessary.) Reduce the heat to medium. Fry the tofu, using a long fork or slotted spoon to nudge the pieces apart if they start to touch (the potato starch is very sticky) and carefully turning the pieces as needed, until they are very lightly browned all over, 8 to 10 minutes. Using a slotted spoon, transfer the pieces to the cooling rack, keeping them from touching. Let the tofu cool for at least a few minutes while you make the sauce.
In another large skillet (preferably nonstick) set over medium-high heat, combine the ketchup, rice syrup and gochujang. Cook, stirring, until the sauce bubbles, 1 to 2 minutes. Turn off the heat.
Return the heat under the frying pot to medium-high, and heat until the oil reaches 350 degrees. Add all the fried tofu pieces; you don’t need to worry about them touching this time. Fry the tofu, turning the pieces with a slotted spoon until they are golden brown and crunchy all over, 4 to 5 minutes. Using the same slotted spoon, transfer the tofu to the cooling rack.
Reheat the sauce over medium-high heat until bubbling. Add the hot fried tofu and gently toss to coat. Transfer to a serving plate, sprinkle with the pumpkin seeds, and serve hot, with rice.