I need to make a small cake with thw WASC recipe can Ifreeze the left over batter, for use later? Or is it better just to bake an extra and freeze tha?
Bake the extra batter and freeze the cake... Frozen cakes are the best
Cake batter can be frozen.
It's easiest to freeze in the cake pan you'll use for baking (if you have enough pans). Or you can just bake the extra batter into a cake layer, and freeze that.
Whatever works best for you; it's all good.
Refrigerating/freezing cake batter and the science of baking powder: