Preheat the oven to 180C/350F/Gas 4.
For the fritters, mix together the eggs, flour and milk in a bowl to make a batter with the consistency of double cream, then fold in the couscous and spring onions.
Heat the olive oil in a frying pan and fry spoonfuls of the fritter batter for 2-3 minutes on both sides, or until golden-brown and crisp.
For the tomatoes, lay the tomato slices on a baking sheet and drizzle over the olive oil and vinegar. Roast in the oven for 5-6 minutes, or until tender.
To serve, place one fritter in the middle of a serving plate, lay a roasted tomato slice on top, followed by a third of the basil. Repeat with another layer of fritter, tomato and basil until you have three layers of each. Serve.