made a salad the other day and left the onion and lettuce tomato out to air by accident, for a day. The taste of the onion and tomato was much sweeter. The air seems to mellow the flavour, and improve it alot.
Next time i make a base i will be cutting the onion up and leaving it out to air for 24 hours, in the hope it may improve the flavour. . I will then do what i usually do. E.G fry the onion in oil gently for 1 hour before making the base. Thought i would share this idea in case it works.