Make the batter: Whisk the gluten-free flour, baking powder, cinnamon, ginger, and salt together in a medium bowl. Set aside.
Make the crumb topping: Mix the gluten-free flour, brown sugar, and cinnamon together in a small bowl. Stir in the melted butter until the mixture is crumbly.
Note 1: Muffin pan sizes vary. This recipe makes between 12 and 15 muffins.