just found this, it might help :)
4 courgettes, sliced lengthways
125g bacon
1 red onion
2 tbsps olive oil
25g butter
100g mushrooms
75g breadcrumbs
2 tbsps parsley
1 free range egg
scoop out the middle of the courgettes, put the shells on a baking tray and chop the flesh
chop bacon and onion and fry for a few mins
remove from pan, leaving the oil
add butter, chopped courgettes and mushrooms to the pan and cook for a few mins
mix everything with the bradcrumbs, parsley and egg, season
spoon into the courgette shells and press down
cover with foil and bake at 190c/170c fan/gas 5 for 20 mins, uncover and cook for another 10 to 20 mins
haven't tried it, yet ;D