Heat some sesame oil and lightly fry sliced onions until translucent. Add chopped garlic and minced ginger and cook until fragrant. Add anise and cinnamon and cook until fragrant. Add chopped potatoes and carrots. Add vinegar, soy sauce, sugar, and oyster sauce, then fill with water until potatoes are covered. Bring to a boil then let simmer for 45 minutes. Add small amount of cold water and corn starch or flour until desired thickness.