Combine dry ingredients and set aside. Combine egg and sugar in another bowl and whisk thoroughly. Add the butter and sour cream and mix well. Combine the Frozen blueberries with the dry ingredients by tossing together. Fold the web ingredients into the berry/dry mixture. DO NOT OVER MIX. Use a food scoop to portion into 12 greased muffin cups. Bake at 350 degrees until light brown, approximately 25 to 30 minutes rotating the muffin pan halfway during the baking. Topping: 1/2 Cup Sugar 1/2 Teaspoon Cinnamon 4 Tablespoons melted Butter After cooling the muffins for approximately 5 minutes top by first dipping the muffin in melted butter and then the cinnamon sugar.