Preheat the oven to 180°C.
Cut the tomatoes and courgette into chunks. Cut the spring onion and garlic into small bits.
Scatter the mushrooms in a roasting dish, then the spring onion and garlic over the mushrooms.. Arrange the tomato chunks, small plum tomatoes and courgette on top.
Mix the oil, marjoram, chilli flakes, vinegar and sugar in a small bowl.Season with salt and pepper to your liking. Drizzle the vegetable with this mixture.
Bake for 10 minutes, then turn over the vegetables with a spoon. Bake for another 10 minutes or until until tender and golden.
Serve warm, garnished with chopped parsley.