Start by removing any damaged or wilted outer leaves from the cabbage. Wash it well, cut out the tough core, and slice it into thin strips.
Heat the oil in a large skillet over medium heat. Add the chopped garlic and sauté until it smells nice and fragrant.
Add the cabbage, carrots, bell pepper, onion, and spring onions to the skillet. Drop in the butter, fresh thyme, pimento seeds (if using), broth, salt, and black pepper. Give everything a good toss so the flavors mix together.
Cover the skillet and let it cook for about 10–12 minutes. Stir every few minutes so nothing sticks to the bottom. The vegetables should be tender but still have a little crunch. Try not to overcook them.
Once everything is cooked to your liking, take it off the heat and serve warm.