2 1/2 cups (10 ounces) white rice flour
1 1/2 cups (10.5 ounces) granulated sugar
1/2 cup (3 ounces) potato starch
4 teaspoons ground pumpkin pie spice
2 teaspoons baking soda
1 1/2 teaspoons salt
1 teaspoon xanthan gum
5 ounces dark chocolate, chopped
4 large eggs
3/4 cup (5 1/2 ounces) canola or vegetable oil
1 (15-ounce) can pure pumpkin (not pumpkin pie filling)
1/2 cup (4 ounces) water
For the Icing
1 stick (4 ounces) unsalted butter, softened or dairy-free butter replacement
4 ounces cream cheese, softened or dairy-free cream cheese
2 cups powdered sugar
1 tablespoon milk or milk replacement