Preheat oven to 400F. Line 12 muffin cups with muffin tin liners.
Soften raisins in water while you make the muffins.
Whisk together whole-wheat flour, all-purpose flour, baking soda, cinnamon, ginger and salt in a large bowl. Whisk together eggs, buttermilk, brown sugar, butter, oil and vanilla in a medium bowl. Add wet to dry ingredients and add raisins and zucchini; stir to combine.
Fill muffin tin liners with batter (the cups will be very full). Bake until golden brown, 25 to 27 minutes. Let cool in the pan for 5 minutes then turn out and let cool completely.