To begin, preheat your oven to 425 and spray a muffin pan with non-stick spray (or use cupcake liners).
In a small mixing bowl, add your flour, cinnamon, baking soda, and salt, and whisk them together till they're well combined.
In a large mixing bowl, add your butter and sugar and cream them together with a hand mixer for a couple minutes. Add your milk, vanilla, and eggs and blend them together again briefly.
Add your wet ingredients to your dry ingredients, and stir them together till well combined. You'll have a very thick muffin batter.
In a separate bowl, add your blueberries and sprinkle a little flour on top (about a couple teaspoons). Stir till the blueberries have been entirely covered in the flour. Then add your blueberries to your muffin batter and gently fold them in.
Fill each muffin cavity to the top. Bake in the oven for 5 minutes, then lower your oven temperature to 350 and bake for 18-20 minutes, or till the muffins are springy to touch and a toothpick inserted comes out clean.
Let cool, then devour!