You may use firm TOFU instead of chicken, or pork as well as thinly sliced beef. If you do not like GOCHUJANG or do not have it, you can omit and use 1 tbsp Oyster sauce. Oyster sauce is packed with sodium so be aware when adding soy sauce to the sauce mixture. I made a large amount of sauce that's why it looks a lot on the picture. I like to save it for later. GOCHUJANG is spicy, so if you cannot handle spicy you may use 1/2 tbsp. to 1 tbsp.