Preheat oven to 325°. Combine cake mix, melted butter and water in a large bowl. Mix vigorously until smooth. Gently fold in the blueberries. Spoon batter into paper-lined muffin tin, filling them ⅔ full. In a small bowl, combine sugar and cinnamon; sprinkle over muffins. Bake 25-28 minutes or until a toothpick inserted in the center of a muffin comes out clean. Makes 12 muffins.
Always check the labels of ingredients in recipes to confirm they are gluten-free, and ensure your space is free from other possible sources of gluten. Since ingredient formulas can change and vary among other brands, Tastefully Simple cannot ensure that prepared recipes will be gluten-free.