Funny coincidence, had them for dinner yesterday:

Cut zucchini in half lenghtwise, with little spoon pull out the inside leaving small rest
Salt and brush with little olive oil, put in oven for a few minutes, put out, set aside.
Filling:
heat olive oil, saute onions, garlic, minced meat or ham, inside of zuchinis, salt and pepper to taste, add herbs as oregano, basil, and tomato paste, add a little liquid (stock or water) until smooth sauce forms, let cook for a while.
Fill in the halves, sprinkle with lots of cheese and bake in oven until cheese melts
Is very nice...
Regards, Martina