Put eggs in boiling water and cook for 9 minutes. Drain, rinse and peel. Peel garlic and chop very finely. Mix yoghurt, salad cream and garlic. Season to taste with salt and pepper. For the vinaigrette, wash parsley and chervil, dab dry and chop finely.
Peel and finely chop the onion. Mix vinegar, mustard, salt, pepper and sugar. Stir in mustard seeds and herbs. Whip the oil into the mixture. Pour the corn on a sieve and let it drain. Peel and roughly dice the onion. Clean, wash and quarter the tomatoes. Clean the lettuce, cut into strips and drain well. Pour tuna on a sieve, drain and then pull apart. Cut ham into strips. Dice eggs. Mix salad, tomatoes, onions, corn and olives and arrange in a large bowl.
Clean, wash and quarter the tomatoes. Clean the lettuce, cut into strips and drain well. Pour tuna on a sieve, drain and then pull apart. Cut ham into strips. Dice eggs. Mix salad, tomatoes, onions, corn and olives and arrange in a large bowl. Add the white sauce, vinaigrette, ham, eggs and extra tuna. Garnish with chervil as desired