I used kaya without skin. If you like, you can use it with skin also. Do not substitute the small onions with the big ones, it will affect the taste. I added more garlic, because I think it gives more punch to this dish. However, if you don't like the garlicky taste, adjust the qty accordingly. I suggest using coconut oil itself for the flavour. Also, make sure that the potatoes and kaya isn't overcooked.