01 - Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or grease lightly.
02 - Whisk together flour, baking powder, baking soda, salt, ground ginger, cinnamon, cloves, and nutmeg in a large bowl.
03 - In a separate bowl, whisk vegetable oil, brown sugar, and molasses until smooth. Add eggs one at a time, mixing thoroughly after each addition. Stir in buttermilk and vanilla extract.
04 - Add wet ingredients to dry ingredients and mix gently until just incorporated. Avoid overmixing to maintain muffin tenderness.
05 - Distribute batter evenly into muffin cups, filling each about three-quarters full. Sprinkle optional coarse sugar and crystallized ginger on top, if desired.
06 - Bake for 18 to 20 minutes until a toothpick inserted in the center comes out clean.
07 - Allow muffins to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.