How to make your own rice flour? Put white rice or brown rice in your blender and grind it as fine as you can – that simple!
Preheat oven to 375* and line a 12 muffin tin with liners.
Make the Streusel topping by combining all the ingredients in a medium bowl. Using your fingers, or a fork, press together until fully combined and it resembles a crumb mix. Set aside.
In a large bowl, whisk together the flours, sugar, baking powder, baking soda, salt, cinnamon, and nutmeg. Add the pumpkin, eggs, melted butter, sour cream and vanilla and mix until combined.
Divide the batter into the 12 muffin liners and top with the streusel topping.
Bake in the oven for 25 minutes, or until a toothpick comes out clean when inserted. Remove and allow to cool.