Wash and slice the courgette and marrow into 4-5mm slices, place in a bowl and sprinkle and toss with 1 tsp of salt. Keep aside for 15 minutes and allow for the water to come out and then pat them dry.
Sauté the dried slices in small batches together with the garlic, parsley and pepper over a medium heat.
Arrange the passata on the bottom of a baking dish and alternate the courgette and marrow slices before sprinkling with grated Parmesan cheese.
Bake in the oven at 180°C for 10-15 minutes until the cheese is golden brown.