smid ‧ gin BrE AmE , smidgen /ˈsmɪdʒən, ˈsmɪdʒɪn/ ( also smidge /smɪdʒ/) noun [singular]
[ Date: 1800-1900 ; Origin: Perhaps from smitch 'bit' (19-21 centuries) ]
informal a very small amount of something SYN touch
smidgin of
I added just a smidgin of chilli sauce.