1. Preheat the oven to 350°F and line two baking sheets with parchment paper.

2. In a large bowl, beat the butter, brown sugar, and granulated sugar until light and fluffy.

3. Mix in the egg, 1 teaspoon vanilla extract, and mashed sweet potato until smooth.

4. In a separate bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, and salt.

5. Gradually add the dry ingredients to the wet ingredients and mix just until a soft dough forms.

6. Scoop the dough onto the prepared baking sheets, spacing the cookies about 2 inches apart.

7. Bake for 11 to 13 minutes, until the edges are lightly golden and the centers are set.

8. Let the cookies cool on the pan for 5 minutes, then transfer them to a wire rack to cool completely.

9. In a small bowl, whisk together the powdered sugar, milk, honey, and 1/2 teaspoon vanilla extract until smooth.

10. Drizzle the glaze over the cooled cookies and sprinkle with chopped pecans if using.

11. Let the glaze set before serving.