Vegan Chocolate Pumpkin Doughnuts

1½ cups sweet white sorghum flour
1 cup finely ground brown rice flour
½ cup potato starch
¼ cup tapioca starch
¾ cup cocoa powder
1 teaspoon xanthan gum
4 teaspoons baking powder
¾ teaspoon salt
1 teaspoon ground cinnamon
½ teaspoon ground cardamom
½ teaspoon cloves
1 cup sugar, plus more for dipping doughnuts
3 tablespoons vegan butter
2 tablespoons ground flaxseeds mixed with 4 tablespoons water
1 teaspoon vanilla extract
½ cup coconut cream
1 cup canned pumpkin
Vegetable oil for frying