Cut the pork loin into 1-inch cubes and marinate for 30 minutes.

Dice the green, red, and yellow bell peppers after removing the seeds, and dice the onion; mix the seasoning ingredients in a bowl and set aside.

Heat oil in a pan to about 300°F, coat the pork in sweet potato starch, and fry until golden brown. Remove and drain the oil.

Briefly fry the green, red, and yellow bell peppers in the oil, then remove; do the same with the onion and set aside.

Pour out the frying oil, sauté the onion briefly, add the seasoning and bring to a boil, then add the fried pork and stir-fry. Finally, add the bell peppers, mix well, and serve.