introducing the ground cumin:ground coriander seed ratio
this might just be limited to the array of spices that i tend to use in my regular cooking, but i have found that i can tweak something tasting "sweet" or "savoury" by adding/subtracting amounts of cumin powder or coriander powder. higher cumin reads more savoury to me and higher coriander reads sweeter to me, all other things being equal.