A lot of things get interesting if you substitute for an ingredient, but I'm trying to beat a psychological barrier.
I have a friend with a strange fad - he will not eat anything red. He is quite sensible about this, and if you cook a meal using tomatoes he will eat it providing that the finished product is not red - like bolognese sauce finishes up brown, for example. And he must not see the tomatoes before they are cooked!
But it gets taxing trying to find substitutes for tomatoes when they are so commonplace in many dishes. So any help with this problem would be appreciated.