Cook the Spaghetti as per instructions on pack. Drain and rinse thoroughly with boiling water. Cut the courgettes in half lengthways and then into slices. Heat the oil in a large pan and fry the courgettes and garlic for a few minutes until softened. Add the lemon zest, tomatoes and 1tbsp hot water. Cook for a further 2-3 minutes until the tomatoes start to soften. Remove from the heat and stir in the Brie so it just starts to melt. Season well with freshly ground black pepper and lemon juice. Toss in the spaghetti and coat well with the cheese mixture. Serve with a fresh green salad.