Heat oven to 400°F. Line a 12-cup muffin pan with paper liners.
Whisk flour, baking powder, baking soda, salt, cinnamon, ginger, and nutmeg in a large bowl.
In another bowl, whisk sweet potato, brown sugar, granulated sugar, buttermilk, oil, and vanilla until smooth.
Fold the wet mixture into the dry ingredients just until no dry streaks remain.
Stir in the chopped pecans. Do not overmix.
Divide batter among liners, filling about three-quarters full. Sprinkle with turbinado sugar and extra pecans.
Bake 16–19 minutes, until domed and a tester comes out clean or with a few moist crumbs.
Cool in pan 5 minutes, then move muffins to a rack to finish cooling.
Notes
Swap buttermilk with whole milk plus 2 tsp lemon juice for a quick substitute. Add 1/2 cup chocolate chips or dried cranberries for a fun twist. Store airtight at room temperature for 2 days or freeze up to 2 months.This recipe is an original creation inspired by classic Sweet Potato Pecan Muffins flavors. All ingredient ratios and instructions are independently developed.