Pre-heat oven to 220 C / Gas no.7 / 425 F.
In a pan sauté onion and mushrooms with oil until softened.
Reduce heat and stir in crumbs, tomato and seasoning.
Slice courgettes lengthways and scoop out some of the flesh with a teaspoon.
Chop up the scoops of courgette and add to pan.
Lay courgette "boats" in a shallow ovenware dish and spoon on filling.
Pour a couple of tablespoons of water in the base of the dish and cover with tin foil.
Bake for 25-30 mins until courgettes tender.