Preheat oven to 350°F In a medium bowl whisk together the flour, xanthan gum, baking soda, salt, cinnamon, nutmeg, allspice, and ginger. Whisk together well.
In a large bowl combine the sweet potato, oil., agave syrup and vanilla mix well at low speed
Add the flour dry ingredients mixture to the wet ingredients and mix at low speed until combined.
Fold in the raisins and cranberries.
Spoon batter into a lined muffin tin, filling to just below tops. (1/4 cup of batter)
Bake 20- 25 minutes until tops of muffins bounce back when pressed lightly. Remove from oven and let stand 5 minutes. Remove muffins from pan and cool on a rack. Store cooled muffins in an airtight container. Makes 18 muffins.
Or you can make one 9 by 5 loaf, Grease a 9 by 5 pan sprinkle with a little gluten free flour and fill the pan with the batter. Bake at 350 for 30 minutes, rotate the pan , reduce the temperature to 325 degrees and bake for 40 minutes more or until lovely golden brown and a tester inserted into the center of the cake comes out clean., let cool for about 20 minute.