Cook the pasta in salted boiling water for about 8 minutes until just tender. Drain. While the pasta is cooking, heat the oil in a frying pan on the hob and gently fry the courgettes for about 5 minutes, turning frequently, until they colour.
Flake the tuna into chunky pieces and mix with the cottage cheese in a bowl. In a separate bowl, mix the tomatoes with the tomato paste, sugar, salt and pepper.
Scatter half the pasta over the bottom of a shallow ovenproof dish and arrange a layer of half the tuna mixture, then a layer of half the courgettes on top. Spoon over half the tomatoes. Repeat the layering with the remaining ingredients, finishing with tomatoes.
Sprinkle with the cheese and cover with foil. Place on the lower rack of the halogen oven.
Set the temperature to 200°C (392°F) and cook for 15 minutes. Remove the foil and cook for another 5–10 minutes until lightly browned. Serve with a leafy salad.