Prepare Roasted Carrot Puree: Preheat oven to 400°F (205°C) with a rack in the center position.
Toss the chopped carrots and vegetable oil on a half sheet pan. Roast for about 40 to 50 minutes, flipping once or twice, until carrots are very tender and lightly caramelized .
Allow the carrots to cool for 10 to 15 minutes. Add carrots to the bowl of a large food processor. Add the water and orange juice, and puree until mostly smooth. You might need to scrape the bowl down with a spatula a few times, it will be on the thick side. Allow to cool to room temperature before using.
Prepare Muffins: Preheat oven to 350°F (175°C) with a rack in the center position. Lightly grease a 12-cup muffin tin or line with paper liners. Set aside.
In medium bowl, whisk together all-purpose flour, whole wheat flour, cinnamon, baking soda, salt, ginger, and baking powder. Set aside.
In a large bowl, combine sugar, oil, and eggs. Whisk until smooth. Add the milk and vanilla extract and whisk until smooth. Add the dry ingredients to the wet ingredients and whisk together until the flour has just been absorbed. Whisk in the carrot puree.
Divide the batter evenly among the greased or lined muffin tin. Bake for 24 to 27 minutes, or until a toothpick inserted in center comes out clean. Set on a wire rack and allow the muffins to cool in the pan for about 5 minutes. Remove from the pan and allow to cool completely on a rack. Serve.