Slice the sausage into bite-sized pieces. Chop the cabbage, dice the bell peppers and onions, and mince the garlic.

In a large skillet, heat a tablespoon of oil over medium-high heat. Add the sausage and brown for about 5 minutes.

Add the onions and garlic to the skillet and sauté for about 2 minutes until onions are translucent.

Add the chopped cabbage and bell peppers, stir-frying for 3-4 minutes until they soften slightly.

Pour in soy sauce and sesame oil, adding red pepper flakes if desired. Cook for another 5 minutes.

Taste and adjust seasoning. Serve immediately.