Drain your tofu and either A) cut into approximately 1" cubes or B) tear into irregular pieces for crispy tofu nuggets. Lay tofu pieces on one half of a clean, lint-free kitchen towel. Fold over the other half of the towel and gently press to remove excess liquid. Leave the tofu to drain for at least 15 minutes.
In the meantime, preheat your oven to 425°F and line a baking tray with parchment or a silicone baking mat.
Transfer the pressed tofu to a mixing bowl. Drizzle with oil and sprinkle in salt and pepper. Toss until evenly coated. Try to be gentle so that the tofu cubes or nuggets stay intact. I find using a big flexible rubber spatula helps.
Sprinkle the cornstarch over the seasoned tofu and once again toss until tofu is evenly coated and there's no dry cornstarch left at the bottom of the bowl.
Arrange the tofu on your prepared baking sheet so that the pieces aren't touching. Bake for 15 minutes and give the pieces a flip. Bake for an additional 15-20 minutes, or until the tofu is as crispy as you like it! The time will vary a little depending on how thoroughly you pressed your tofu.
While your tofu bakes, measure ingredients for the gochujang sauce.