- Separate the egg yolks and whites. Chop the leeks finely; set aside.
- In a skillet, heat oil then put leeks in it and saute at a medium heat for about 3 minutes while stirring occasionally.
- Then add vegetable soup to pan, reduce the heat and simmer gently for 5 minutes more.
- Put the walnuts in a blender and blend until finely chopped. Then put leek mixture in it and blend to form a puree. Pour into the mixing bowl.
- Then put together the basil, chives, yogurt and egg yolks until completely combined.
- Ladle the egg mixture into leek puree. Season and mix well.
- Beat the egg whites in a separate mixing bowl until firm peaks form. Fold the egg whites into the leek mixture. Put the mixture lightly greased 900 ml soufflé dish and place on a warm baking tray.
- Then put it in a preheated oven for about 40 minutes or until risen and set. Serve immediately.