2 x 185 g (6 1/2 oz) cans tuna in brine or oil, drained
125 g (4 oz) grated cheese (such as Cheddar cheese, Emmental or mozzarella)
crusty bread, to serve (optional)
Bring a large pan of water to the boil and cook the gnocchi for 2–3 minutes or according to the packet instructions until they rise to the surface of the water. Drain well and return to the pan.
Meanwhile, gently warm the ratatouille in a saucepan with the tuna, then pour over the gnocchi and stir gently to combine. Tip into a large, buttered ovenproof dish, then scatter with grated cheese and cook in a preheated oven, 220˚C (425˚F), Gas Mark 7, for about 15 minutes until bubbling and golden. Spoon into dishes and serve with crusty bread, if desired.