Start by sifting the gluten-free flour, baking powder, baking soda, cinnamon, nutmeg, and low carb brown sweetener into a large mixing bowl.
In a separate bowl, combine the pumpkin puree, milk, egg, and melted butter, whisking thoroughly until the mixture is smooth.
Gradually add the wet ingredients to the dry ingredients, folding them together gently until they are just combined. Take care to avoid overmixing to keep the pancakes light and fluffy.
Warm a non-stick skillet or griddle over medium heat and lightly coat it with butter or cooking spray.
Drop small portions of the batter onto the heated skillet using a cookie scoop or a small ladle, aiming for pancakes that are about 3 to 4 inches in diameter.
Allow the pancakes to cook for about 2 to 3 minutes on each side, flipping once when you see bubbles forming on the surface and the edges begin to look set.
Serve the pancakes hot, topped with maple syrup, a dollop of whipped cream, and a scattering of chopped walnuts for a delightful finish.