Sylvia, most of my recipes call for hot water...if you just want to reduce the potassium, could you
use instant coffee and make it half-strength? Hopefully, someone who knows what they're talking about will come along and help you. I'd probably just use a recipe with hot water.
Instant coffee, regular, prepared with water,6oz. serving: K+ 53.7 mg
Instant coffee, decaf, prepared with water, 6oz. serving: K+ 64.4 mg
How about changing the lt. brown sugar to dark brown, and adding a little brandy in with water to give your gingerbread a dark, rich flavor?
Anyway, the link provided may be of some help. I couldn't live without it. It is very clear, and gives indepth nutritional data for more foods than you would imagine...