I want to make a half sheet cake. I have one quarter sheet pan. If I let the 2nd half of the batter sit while the first one bakes, is that okay? Or do I need to get the batter in the oven quickly after mixing so that the leavener can still do its job? I'm probably going to use the kakeladi's WASC recipe.
It depends on your batter but it could be problematic. Can you just make a half batch of batter twice?
It also depends on your baking powder. I use aluminum-free, so it has to go in quickly, I've read.
When I have extra batter, I put it in the refrigerator while the other cake is baking, to retard the leavening action.
There's "slow acting" baking powder but most of us don't have access to that.
I think I'm going to just prepare the batters separately. No use in messing with a batter that's been lying around.
In the future, if I start to bake more half sheets, I'll just buy a half sheet pan.