Start by piercing a sweet potato several times with a fork, then microwave it for 5-7 minutes until tender. Alternatively, roast the potato at 400°F for 45-60 minutes until fully cooked. Once cool enough to handle, scoop out the flesh and mash it until smooth.

In a mixing bowl, beat together 1/2 cup of softened unsalted butter with 1/2 cup brown sugar and 1/4 cup granulated sugar until light and fluffy, about 2 minutes. Blend in one egg, 1 teaspoon of vanilla extract, and the mashed sweet potato until well combined.

In a separate bowl, whisk together 1 1/2 cups of all-purpose flour, 1 teaspoon of ground cinnamon, 1/4 teaspoon of nutmeg, 1/4 teaspoon of ground ginger, 1 teaspoon of baking soda, and 1/2 teaspoon of salt.

Gradually add the dry mixture into the wet ingredients, stirring gently until just combined. Avoid overmixing to keep cookies soft.

Preheat your oven to 350°F. Using a rounded tablespoon, drop dough onto parchment-lined baking sheets. Optionally, press a pecan half into each cookie or sprinkle cinnamon sugar on top. Bake for 10-12 minutes until the edges are golden brown.

Remove cookies from the oven and let sit for 5 minutes on the baking sheet, then transfer them to a wire rack to cool completely.