Cut the cod into bite-sized pieces, sprinkle with salt and pepper (not listed in ingredients), and let sit on a paper towel for about 15 minutes. Pat dry any moisture that comes out.

Mix the sauce ingredients together. Finely chop the onion. Shred the lettuce into thick strips.

Lightly coat the cod with cornstarch. Heat a generous amount of oil in a frying pan and cook the cod until browned on both sides, then remove from the pan.

Clean the pan, add more oil, and sauté the chili bean paste. Once fragrant, add the onion and sauté until soft.

Add the prepared sauce and cook until it thickens. Return the cod to the pan and coat with the chili sauce. Serve on a plate lined with lettuce.