Preheat the oven to 350 degrees F and line a standard 12-cup muffin tin with paper liners. Spread the wheat bran evenly on a rimmed baking sheet and bake until fragrant and toasted, about 8 minutes. Remove the bran from the oven and increase the heat to 450 degrees.
In a medium bowl, whisk together the toasted bran, graham flour, all-purpose flour, baking powder, cinnamon, salt and cloves. In a large bowl, whisk together the molasses, vegetable oil, dark brown sugar and eggs. Stir in the buttermilk, raisins and ginger.
Gently stir the dry ingredients into the wet ingredients, just until everything is evenly moistened. Don't overdo it.
Divide the batter evenly among the prepared cups. Transfer to the oven and immediately reduce the temperature to 350 degrees F. Bake until the tops are nice and puffed and a toothpick inserted into the center comes out with moist crumbs attached, 22 to 25 minutes. Transfer the muffins to a rack to cool completely.