DD (15) has decided to become vegetarian (we are a week in and she seems committed). She is quite a faddy eater so hurrah for the added challenge of vegetarianism (not) - although perhaps it might work out well if in order to eat she now needs to embrace other foods!
In her packed lunch she used to take a large ish section of baguette with either chicken, tuna, ham etc in it. This morning I have put in a large ish piece of baguette with grated cheese and marmite - but can't keep repeating that day in day out. She has suggested strawberry jam as a filling for another day and lemon curd for another day 
The rest of her lunch box isn't a problem - packet of crisps, 2 or 3 pieces of fruit and a club biscuit or similar, its just the 'core' item I am struggling with
She eats a reasonable range of fruit and vegetables but isn't keen on tomatoes (likes tomatoes in cooked meals such as pasta sauce or casserole but doesn't love whole or part tomatoes - might be texture), doesn't like berries, doesn't like mushrooms and wouldn't do olives
Any advice gratefully received - I admire her choice and would like to support her