Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.

In a large bowl, whisk together the pumpkin puree, vegetable oil, brown sugar, granulated sugar, eggs, and vanilla extract until well combined.

In another bowl, sift together the all-purpose flour, baking powder, baking soda, cinnamon, nutmeg, ginger, and salt.

Gradually add the dry ingredients to the wet mixture, stirring until just combined. Do not overmix. If using, fold in the chopped walnuts or pecans.

Spoon the batter into the prepared muffin tin, filling each cup about two-thirds full.

Bake for 18-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.

While the muffins are baking, prepare the maple icing by whisking together the powdered sugar, maple syrup, and milk in a small bowl until smooth. Adjust the milk as needed to achieve your desired consistency.

Allow the muffins to cool for a few minutes in the tin before transferring them to a wire rack to cool completely.

Once the muffins are cooled, drizzle the maple icing over the top of each muffin. Serve and enjoy!