Simmer boneless chicken and vegetables with gochugaru, tomato puree, allulose, and soy sauce.
Cut the chicken tenderloin into bite-sized pieces.
Slice the onion and bell pepper into thin strips.
Heat olive oil in a pan and stir-fry the chicken tenderloin.
When the chicken is golden, add the onion and bell pepper and continue to stir-fry.
Season with salt and pepper.
Add the tomato sauce and simmer for 5 minutes, stirring occasionally.
Top with mozzarella cheese, cover with a lid, and cook until the cheese melts.