Gluten-Free Cake Donuts with Chocolate Glaze

Ingredients

• 2 1⁄4 cups millet flour, plus more for dusting
• 1⁄4 cup plus 2 tbsp. potato starch
• 1⁄4 cup tapioca starch
• 1⁄4 tsp. ground cinnamon
• 1 tsp. baking powder
• 1 tsp. kosher salt
• 1⁄2 tsp. xanthan gum
• 1⁄4 tsp. freshly grated nutmeg
• 1⁄4 tsp. baking soda
• 1⁄2 cup plus 2 tbsp. unsalted butter, softened
• 1⁄3 cup sugar
• 1 egg
• 1 tsp. vanilla extract
• 1⁄2 cup buttermilk
• Canola oil, for frying
• 2 oz. semisweet chocolate, finely chopped
• 1 cup confectioners' sugar
• 2 tbsp. milk