If you have an ethnic food store in your area, pick up some annato seed. It is very inexpensive. Put some of the seeds,maybe a tablespoon or so, in with some oil of your choice and just let it hang out for a week or so. Use some of that oil in a batch and a fabulous yellow will result. I am not a precise person, except when I must be, so the amount of the colored oil you use is up to you. The seeds can be reused at least once.