Put the pasta in boiling salted water and cook over medium heat for 8-9 minutes. Then pour onto a sieve, rinse with cold water and drain well. Drizzle spaghetti with oil. In the meantime, put eggs in boiling water and let it boil for 9 minutes, drain, quench and peel. Quarter the eggs and chop roughly. Meanwhile clean and wash spring onions and cut them into fine rings. Clean, wash and halve the tomatoes.
Put the tuna fish on a sieve, drain and tear apart with a fork. Peel garlic and chop very finely. Mix yoghurt, vinegar, salad cream and garlic. Season to taste with salt, pepper and sugar. Mix spaghetti, spring onions, tuna, eggs, cherry tomatoes and olives. Pour sauce over it, mix and let it soak through. Serve on lettuce leaves garnished with basil