To Make Burnt Sugar Mixture: Melt 1 cup white sugar in a pan till medium brown. Slowly stir in 1/2 cup boiling water.
Preheat oven to 160 degrees C.
Sift together into mixing bowl the flour, 1 1/2 cups white sugar, baking powder and salt. Form a well in the dry ingredients and add the vegetable oil, egg yolks, burnt sugar mixture, cold water and vanilla. Beat with wooden spoon until smooth.
Beat egg whites and cream of tartar in large bowl until they hold very stiff peaks. Pour egg yolk mixture in a thin stream over egg whites. Fold in gently. Pour batter into an ungreased ring tin.