Preheat the oven to 180C.
Grate the zucchini and the apple. Place them in a cloth and squeeze water out of them as much as you can. Set aside.
Then in a large bowl, mix all the wet ingredients with a spatula: the olive oil, yoghurt, eggs, vanilla, and sugar until they mixture is homogeneous.
Add the dry ingredients: flour, salt, baking powder, cinnamon, and nutmeg. Mix with a spatula.
Fold in the koussa, apple, raisins and walnuts
Line a loaf tin with baking paper or brush it with tahini. Pour the batter and bake at 180C for about 45 minutes or until a testing skewer comes out clean.