Pierce a medium sweet potato and microwave for 5–7 minutes until tender, or roast at 400°F for 45–60 minutes. Let cool, peel, and mash until smooth to make ½ cup sweet potato puree.

In a mixing bowl, beat ½ cup softened unsalted butter with ½ cup brown sugar and ¼ cup granulated sugar for about 2 minutes until fluffy. Add in sweet potato puree, one egg (or flax egg), and 1 teaspoon vanilla extract; blend until creamy.

In another bowl, whisk together 1 ¼ cups all-purpose flour, 1 teaspoon baking soda, 1 teaspoon cinnamon, ½ teaspoon nutmeg, ½ teaspoon ginger, and a pinch of salt.

Gradually fold dry ingredients into the wet mixture using a spatula. Mix until no flour streaks remain, being careful not to overmix.

Preheat oven to 350°F. Line a baking sheet with parchment paper. Scoop tablespoon-sized balls of dough onto the sheet, spacing them 2 inches apart. Bake for 10–12 minutes until edges are golden and centers are soft.

Let cookies rest on the baking sheet for about 5 minutes before transferring to a wire rack to cool completely.