Preheat the oven to 350˚F and spray 2 9-inch loaf pans with cooking spray.
Mix the dry ingredients in a large bowl (including the sugar).
In the bowl of a large standup mixer, cream the butter. Then add the eggs, one at a time, and beat until fully incorporated. Add the milk and beat until mixed. Add the pumpkin and zucchini and mix on medium until blended.
Take bowl away from standup mixer. Add bowl of dry ingredients and stir with a wooden spoon until all is moistened. Do not overmix.
Bake for 45 - 60 minutes or until top is golden brown and a knife inserted comes out clean. Allow to cool for at least 10 minutes before removing from the pan.
Recipe by StreamingGourmet at http://blog.streaminggourmet.com/2012/10/07/pumpkin-zucchini-bread/