Wash the zucchini well and cut them into 2 lengthwise. Remove the seeds and then with a spoon, hollow out the zucchini te keep pulp.
Heat some olive oil in a frying pan, brown the chopped onion, then add all the ingredients. Stir well, and let cook 5-10 minutes. Stir again and gently stuff the zucchini.
Bake for 30 minutes at 200 degrees and serve warm or at room temperature.