You can make the quick version the day of, or start the day before to allow it to ferment. Fermentation not only helps break down the grain and reduce phytic acid, but it also adds a deliciously tangy flavor.
Do you need this recipe to be dairy free? You can use coconut oil rather than butter in the crumb topping. Also, swap out the milk for almond or coconut milk. The flavor will be slightly different, but still very yummy.