You can make this recipe without star anise and cloves. It will be delicious but less complex. The "core" of the braising liquid is water (or chicken broth), soy sauce, ginger, and garlic - these four ingredients are absolutely necessary. Star anise and cloves add extra flavor, spice, and depth...but don't let not having these two ingredients stop you from making the dish. P.S. Braising liquid is very open to adaptation. As long as you have the four "core" ingredients, feel free to change and add spices. Think bay leaves, whole peppercorns, a cinnamon stick, etc.