Brown the Butter – Place butter into a small skillet and cook over medium heat for about 5-8 min while stirring consistently. – When the foam on top of the butter becomes a golden brown color and the melted butter underneath is darker and has specks in it, remove the pan from the heat. – Immediately pour the butter into a bowl, specks and all. – Set the bowl into fridge for 1 hour or into freezer for 15 minutes before using.
Preheat oven to 400 degrees F and line a muffin pan with paper liners or grease well.
In a large bowl, sift together the flour, baking soda, baking powder, sugar, salt, and cinnamon. Make a well in the center and set aside.
Add cooled browned butter (specks and all) to another bowl and add in the buttermilk, vanilla, and beaten eggs. Whisk well to combine.
Pour the wet ingredients into the well of the dry sifted ingredients and stir to combine.
Spoon the batter into the muffin cups. Makes about 15-18 muffins (varies on amount due to size of frozen blueberries). Sprinkle additional sugar over the tops, if desired.
You can DIY buttermilk by measuring one cup of milk (dairy free or regular milk) and removing one tablespoon of liquid.
Then add in 1 tablespoon of lemon juice or white vinegar (depending on what you have).