1. Preheat the oven to 350F. Generously grease a 10 by 4 inch loaf pan. Line the bottom of the pan with parchment paper.
2. In a bowl, swift together the flour, baking soda, baking powder and 1\4 teaspoon salt. Keep aside.
3. In a small bowl mix together cocoa and oil and blend well to make thick paste. Add 1or 2 more drops of oil if the mixture is difficult to stir.
4. In the bowl of an electrical mixer, blend the oil with the sugar until light and fluffy, scraping the bowl often. Add eggs one at a time and blend well, until pale and creamy. Stir in the vanilla and water. Then fold in dry ingredients.
5. Remove one third of the batter to a smaller bowl. Add chocolate paste and stir to make a chocolate batter.
6. Using a metal spoon or spatula pour alternating layers of white and chocolate batter into the prepared pan. (Don't stir the better. It works out in the baking.)
7. Bake for 40-45 minutes or until the cake is lightly browned on top and spring back when lightly pressed. Cool in the pan for 15 minutes. Then glaze it with orange glaze.
To make glaze, Combine sugar, orange juice and orange zest to make a thick paste. Drizzle this over the top of the cooled cake.