Preparation Position rack in lower third of oven and preheat to 400°F. Butter muffin pan and lightly dust with tapioca flour, knocking out excess. In large bowl, whisk together tapioca flour, cornmeal, rice flour, cornstarch, sugar, baking powder, baking soda, and salt. In medium bowl, whisk together butter, milk, maple syrup, and eggs. Using wooden spoon, stir wet ingredients into dry ingredients until fully combined. Gently fold in blueberries. Divide batter among muffin cups, filling each cup 3/4 full. Bake until tops are domed and feel springy to the touch, and toothpick inserted in center comes out clean, about 15 minutes. Let cool in pan 5 minutes, then turn out onto wire rack.
Preparation Position rack in lower third of oven and preheat to 400°F. Butter muffin pan and lightly dust with tapioca flour, knocking out excess. In large bowl, whisk together tapioca flour, cornmeal, rice flour, cornstarch, sugar, baking powder, baking soda, and salt. In medium bowl, whisk together butter, milk, maple syrup, and eggs. Using wooden spoon, stir wet ingredients into dry ingredients until fully combined. Gently fold in blueberries. Divide batter among muffin cups, filling each cup 3/4 full. Bake until tops are domed and feel springy to the touch, and toothpick inserted in center comes out clean, about 15 minutes. Let cool in pan 5 minutes, then turn out onto wire rack.