Gluten-free cooking spray
2 cups (14 ounces) granulated sugar
1 cup (4 ounces) sorghum flour
1/2 cup (2.75 ounces) potato starch
1/2 cup (1.5 ounces) cocoa powder, Dutch-process or natural
1/2 teaspoon salt
1/4 teaspoon baking powder
1/4 teaspoon xanthan gum
3/4 cup vegetable oil
3 large eggs
1/4 cup water

1. Adjust oven rack to middle position. Preheat oven to 325°F. Spray 13- by 9-inch pan with cooking spray.
2. If Mixing By Hand: In large bowl, whisk together granulated sugar, sorghum flour, potato starch, cocoa powder, salt, baking powder, and xanthan gum. Add vegetable oil, eggs, and water. Whisk until thoroughly combined. Batter will be thick.
3. If Using a Food Processor: Combine granulated sugar, sorghum flour, potato starch, cocoa powder, salt, baking powder, and xanthan gum in bowl of food processor. Process for one minute. Add vegetable oil, eggs, and water. Blend until thoroughly combined. Batter will be thick.
4. Spread batter into prepared pan. Bake until toothpick inserted into the center of brownies comes out with only a few damp crumbs clinging to it, about 40 minutes. Allow brownies to cool in pan. When cool, cut into 24 squares and serve. Store brownies in an airtight container on the counter for up to three days. Cooled brownies can be frozen for up to six weeks.