I make this recipe for muffins all the time! I like to vary it up a bit by adding either raisins or chunks of apple. My suggestions is to use a good firm apple like a cortland, but a mac would do. You can use a mixture of whole wheat and all-purpose flour, or only whole wheat. I have not tried it with only all-purpose, so I won't guarantee results. I subbed in plain applesauce for the oil, as well as Splenda brand sweetner for the sugar. I do this every time I make these muffins and they turn out perfectly!