Dice the pork sirloin into bite-sized pieces. Chop the cabbage into 1-inch pieces.
Heat 1 tablespoon olive oil in a dutch oven over medium heat. Add the pork to the skillet and cook, stirring often, until pork is nearly cooked through, about 8 minutes.
Add the onion, garlic, and cabbage to the skillet. Drizzle the remaining tablespoon of olive oil over the skillet and sprinkle with the salt and pepper.
Cook the cabbage, stirring constantly, until it becomes tender, about 10 minutes.