How to Make It
Preheat oven to 375°.
Weigh or lightly spoon 6 ounces brown rice flour (about 1 cup) and white rice flour into dry measuring cups; level with a knife. Combine flours, 1/3 cup sugar, and next 6 ingredients (through salt) in a medium bowl; stir with a whisk. Make a well in center of mixture. Combine yogurt and next 4 ingredients (through egg); stir with a whisk. Add to flour mixture, stirring just until moist.
Toss raspberries with 1 tablespoon brown rice flour in a small bowl; gently fold into batter.
Place 12 paper muffin cup liners in muffin cups; coat liners with cooking spray. Spoon batter into prepared cups, and sprinkle with 1 teaspoon sugar. Bake at 375° for 22 minutes or until lightly browned and muffins spring back when lightly touched. Cool 10 minutes in pan on a wire rack; remove from pan.