Preheat the oven to 180°C (350°F). Place muffin paper cups on a muffin tray.
In a large bowl, combine all dry ingredients: all-purpose flour, whole wheat flour, brown sugar, rolled oats, raisins, baking powder, ginger, cinnamon and a pinch of salt. Add the grated carrots.
In another bowl, whisk together the oil, milk, eggs and lemon zest. Add the mixture to the dry ingredients and mix gently with a spatula until the mixture is slightly moist. Divide the batter evenly among the cups.
Bake in the center of the oven for 25 minutes or until a toothpick inserted in the center of a muffin comes out clean.