i tried the par boil again with v.good results. i've adopted this going fwd.
i used turmeric (1 tsp), a little oil (1 tbsp), ~300ml water and 3 off "fine" chopped "5mm" onion.
big surprise - no onion pong. i'm not sure which stopped the pong - i guess the turmeric given the small amount of oil in comparison to water.