I'm planning to attempt the
ginger cookie recipe that hasn't quite come out right for me in the past (they didn't spread they way the picture indicated they should) with baking soda instead of baking powder and see if they turn out better.
(I'm unclear if there's a difference between UK self-raising flour and US self-rising flour. iirc most the recipes for making self-rising flour involve adding 1.5 tsp baking powder and 0.25 tsp salt to 1 cup flour, but the chocolate chip cookies I made the other day used baking soda so I figure it's worth a try.)