Preheat oven to 350°F and coat two loaf pans with non-stick cooking spray.
Mix the butter, oil, applesauce and sugar. Add the eggs and vanilla.
Combine the milk and vinegar.
In another bowl stir together the flour, cocoa, baking soda, baking powder and salt.
Slowly add the milk mix and dry ingredients, alternatively to the sugar mixture. Mix well.
Stir in zucchini by hand and pour into two loaf pans.
Combine chocolate chips, walnuts and brown sugar and sprinkle over both mixtures.
Bake for 40-45 minutes or until toothpick comes out of loaves clean.