Gochujang Tofu

Name: Gochujang Tofu
Prep time: 20 min
Cook time: 35 min
Total time: 55 min
Cuisine: Korean
Ingredients: 1 block firm or extra-firm tofu; 1 tablespoon olive oil (or other neutral oil); 2 tablespoons cornstarch (or potato starch); pinch salt and pepper; 3 tablespoons gochujang; 2 tablespoons ketchup; 1 tablespoon mirin; 1-2 tablespoons soy sauce (divided); 1 tablespoon brown sugar; 4 cloves garlic (minced); 1 tablespoon rice vinegar; 2 teaspoons toasted sesame oil; 2-4 tablespoons water (or as needed); 2 thinly sliced scallions; toasted sesame seeds