In a bowl or plastic bag, combine sorghum flour, quinoa flour, tapioca starch, sugar, baking powder, baking soda, xanthan gum, salt and cardamom. Mix well and set aside.
In a separate bowl, using an electric mixer, beat the egg, milk, oil and vinegar until they are combined. Add the dry ingredients and mix just until combined. Stir in the cranberries and pistachios.
Lightly grease a 6-cup muffin pan.
Spoon the batter into the prepared muffin cups, dividing it evenly. Let the batter stand in the pan for 30 minutes.
Meanwhile, preheat the oven to 350°F (180°C).
Bake for 18 to 20 minutes or until the muffins are firm to the touch. Remove them from the pan immediately and let them cool completely on a rack.