Pierce the sweet potato several times with a fork, microwave for 5-7 minutes until tender, or roast at 400°F for 45-60 minutes. Let cool and mash until smooth.

In a large bowl, combine softened unsalted butter with brown and granulated sugar. Beat on medium speed for about 2 minutes until light and fluffy.

Add sweet potato puree, egg, and vanilla extract to the butter and sugar mixture, and mix until creamy.

In another bowl, whisk together flour, cinnamon, nutmeg, ginger, baking soda, and salt. Mix well.

Gradually add dry ingredients to the wet mixture, mixing just until no flour streaks remain.

Preheat oven to 350°F. Drop portions of dough onto a parchment-lined baking sheet, spacing 2 inches apart. Optionally top with pecans or cinnamon sugar.

Bake for 10-12 minutes until edges are golden. Cool on baking pan for 5 minutes, then transfer to a wire rack.