As Tofu needs to be fried in oil, I highly recommend that you use the less fragile Firm or Extra Firm Tofu. I’ve tried both kinds and they are perfect for frying. To reach a nice crispy texture, I use the double-fry method, which I also like to use in my fried chicken recipes (e.g. Honey-Buttered Korean Fried Chicken with Almonds).
The Sweet and Spicy Sauce is made of Ketchup, Light Syrup, Gochujang, and a little amount of Vegetable Oil. You can substitute the Light Syrup with Rice Syrup or 3 tablespoons of Brown Sugar.