Pierce a medium sweet potato with a fork and microwave for about 5-6 minutes until tender. Alternatively, roast at 400°F for 45-60 minutes. Peel and mash until smooth.

In a large bowl, beat softened butter, brown sugar, and granulated sugar until light and fluffy, about 2-3 minutes. Add egg, vanilla extract, and mashed sweet potato, mixing until combined.

In a separate bowl, whisk together flour, cinnamon, nutmeg, ginger, baking soda, and salt. Combine dry ingredients with wet mixture gently until just combined.

Preheat the oven to 350°F. Scoop dough onto a lined baking sheet, spacing them 2 inches apart. Optionally, press a pecan half into each cookie.

Bake for 10-12 minutes until edges are golden and centers are soft. Cool on the sheet for 5 minutes before transferring to a wire rack.