Grease a muffin tin (or insert paper muffin liners). Set pan aside.

In a medium bowl, add the buttermilk, oil, eggs, vanilla, brown sugar, and molasses. Whisk together until fully combined. Stir in the wheat bran and 1/3 cup of oats; let mixture sit for 15 minutes. (This allows oats to soften.)

Meanwhile, place the raisins in 1 cup of very hot water; set aside to soak. (Tip: This step can be skipped, but I find that soaking raisins in hot water for a few minutes plumps them up a bit.)

In a medium bowl, combine both flours, baking powder, salt, cinnamon, and orange zest. Stir until well combined. After oat mixture has softened, add the flour mixture and stir until just combined. (Do not overmix.)

Drain the raisins; fold the raisins and pecans into the batter.

Fill muffin tins approximately 3/4 full. Sprinkle tops of muffins with remaining 1/4 cup of oats. Bake for 17-20 minutes at 400°F, or until a toothpick inserted into the center of the muffins comes out clean. Turn muffins out of pan onto a baking rack to cool.