Thanks everyone for the suggestions.
I like the sound of JD's caramelised onion & mushroom tarts.
Definitely go with these. A winner every time. Young and old alike.
I get a request for these at least once a week and not just from family. At work my colleagues get me to make them for their parties etc. I always have them in the freezer.
Just one tweak - I do caramelised onion on the stove, less liquid than done in TMX.