Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners or coat it with cooking spray.
In a medium bowl, whisk together the gluten-free flour, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger until well combined.
In a large mixing bowl, combine the granulated sugar, brown sugar, eggs, pumpkin puree, vegetable oil, and vanilla extract. Beat until the mixture is smooth and well combined.
Gradually add the dry ingredients to the wet ingredients, stirring gently with a rubber spatula until just combined. Be careful not to overmix.
If desired, fold in the chopped nuts or chocolate chips.
Divide the batter evenly among the muffin cups, filling each about ¾ full.
Bake in the preheated oven for 18 to 20 minutes, or until a toothpick inserted into the center comes out clean.
Remove the muffins from the oven and allow them to cool in the pan for about 5 minutes before transferring them to a wire cooling rack to cool completely.