1) You can use all whole wheat flour or just all purpose flour in this recipe as well. Using only whole wheat flour will make for a denser cake. 2) Any unsweetened plant based milk can be used for this cake EXCEPT oat milk. I found this out the hard way. Oat milk makes this cake taste very bizarre and not in a good way.3) If coconut oil is very hard smash it with a fork before trying to cream it together with the lemon juice. If the coconut oil is so hard that the fork doesn't break it apart then heat it in a warm water bath or microwave. Heat only until softened, not melted!4.) Do not use treated and waxed lemons to get your lemon zest. Best bet is to use organic lemons. Always check the labels, they should let you know if they are waxed or not.