When scaling down (or scaling up) baking recipes, do you also halve/double/etc the baking powder/soda amount?
I want to bake this: http://smittenkitchen.com/2008/09/maj... but it calls for 3 and half cups of flour. I don't want to use anything more than 2 cups of flour, because I'll probably end up eating most of it if it doesn't turn out very good. (My cake baking skills are suspect, so far, I've only made chocolate cakes and banana cakes, and just twice at that; so I'm not exactly confident about baking cakes)
In general, when scaling recipes, what do you change and what do you not change from the original?