Letting batter with baking soda wait before adding into the oven I want to bake a cake with 3 layers, but I only have one baking pan and thus I will have to bake them one by one (already thought about making one big cake and dividing it into 3 parts but I pref not to use that method).
The problem is it takes 35 minutes to bake one layer and the batter contains baking soda and baking powder and I'm worried it will affect the outcome since I'm not baking the other 2 layers immediately after adding the baking soda.
So my question is, can I let the batter for the other 2 layers wait before adding to the oven?
Making the batter and separating into 3 and then adding the baking soda and powder isn't an option since I would have to mix it again which will affect the result. And I also don't want to make the batter for each layer separately.
I doubt the raw batter will survive 35-70 minutes out of the oven.
Many times when I made homemade cake, things like

forgetting to preheat the oven

taking too long to scrape all the batter into the baking pan

taking too long decorating the top of the cake batter when its in the pan


rewards me with a flat cake.
On the other hand, after adding the wet ingredients to store bought cake mix, surprisingly, letting the batter sit for a long time (like 30 minutes) before popping it into the oven, doesn't really change the finished product!
What I recommend you do is have your wet ingredients combined and dry ingredients combined all ready in two separate containers. For each cake, mix a third of the wet ingredients with the dry ingredients; this would be more practical then making the batter three times.