I brown my onions and garlic before I add them to the slow cooker. This is a personal preference, and not a necessary step. I give more information on this here, but skip this step if you prefer. I prefer to use bone-in chicken thighs for this recipe. I find this cut holds up better in the slow cooker, and the bone adds additional nourishment and taste to the dish. I have not made this with chicken fillet, so cannot provide details on the final dish.