Preheat your oven to 400 degrees F. Line a muffin tin with paper liners.
In a small or medium sized bowl melt the butter. Let the butter cool slightly then add the egg, buttermilk, and vanilla extract. Whisk these ingredients together. Set this aside.
In a large bowl combine the dry ingredients including the flour, sugar, baking powder, salt, cinnamon and light brown sugar.
Add the butter mixture to the flour mixture and mix together. Don't over mix!
Fold in the blueberries. Again, don't over mix!
Using a cookie scoop, scoop the batter into your muffin tin. Bake the muffins for 17-20 minutes or until a toothpick inserted in the center of the muffins comes out clean.
Allow the muffins to cool on a rack and then enjoy!