Heat oven to 400°F. Paper-line or grease muffin cups.

Combine gluten free all-purpose flour, pumpkin pie spice, cinnamon, baking soda and salt in a large bowl. Combine sugar, pumpkin, eggs, oil, water, and vanilla in large mixer bowl; beat until just blended. Add flour mixture to pumpkin mixture and mix until incorporated. Spoon batter into prepared muffin cups. Top each muffin with one to two teaspoons of sugar topping.

Bake 20 to 25 minutes or until wooden pick inserted in centers come out clean. Allow to cool before serving. Recipe is great for making mini muffins as well. Using mini muffin tins that are either lined with paper or greased, fill each cup approximately ¾ full. Bake for 15-18 minutes.

Optional topping: While muffins are baking, combine ¼ cup Granulated Sugar and ¼ cup Brown Sugar. Whisk sugars together in a small bowl until evenly mixed.