All dry ingredients are mixed in a bowl. Zucchini peel, grate and put on paper to absorb excess liquid. In a separate bowl whisk eggs, milk, olive oil and vanilla. Then add courgettes and stirred again. Pour the chopped walnuts and pour the dry ingredients. Stir gently until fully absorbed products. Tray size 15h25 cm greased with sunflower oil and sprinkle with flour. Pour the dough and sprinkle with walnuts and brown sugar. Heat the oven to 180C. Bake for 1 hour or until a stick stuck into the cake, comes out dry.