Step 1: Heat olive oil in a large skillet or wok over medium-high heat. Add the sliced sausage and cook for 5-7 minutes, or until lightly browned and slightly crispy. Remove sausage from the skillet and set aside, leaving any rendered fat in the pan.
Step 2: Reduce heat to medium. Add the diced onion to the skillet and sauté for 3-5 minutes, or until softened and translucent.
Step 3: Add the minced garlic to the skillet and cook for 1 minute until fragrant, being careful not to burn it.
Step 4: Add the thinly sliced cabbage to the skillet. Stir-fry for 5-7 minutes, or until the cabbage has softened to your desired texture but still retains a slight bite.
Step 5: Return the cooked sausage to the skillet with the cabbage and aromatics.
Step 6: Pour in the chicken broth, soy sauce (if using), black pepper, and red pepper flakes (if using). Stir everything together well, ensuring the cabbage and sausage are coated.
Step 7: Cook for another 2-3 minutes, allowing the flavors to meld and the sauce to slightly reduce. Taste and adjust seasonings as needed.
Step 8: Remove from heat. Garnish with fresh chopped parsley or green onions before serving.