Pre-heat your oven to 350 degrees.
Make sure that your 1/2 cup of unsalted butter is at room temperature. If so, add it to your stand mixer or bowl (if using a hand mixer) and pour in 1 1/4 cups granulated sugar. Cream the unsalted butter and granulated sugar together on medium speed until they are well combined. This should take about two minutes.
Let's add our eggs to the creamed butter mixture! Mix in one egg at a time. After both eggs have been mixed in then add in 2 tsp of vanilla extract. Once everything is mixed together and has reached a creamy consistency, set aside.
Now, let's combine our dry ingredients. Grab a medium size mixing bowl and add in 2 1/2 cups of unbleached flour, 2 tsp baking powder, 1 tsp salt, and 1 tsp ground cinnamon. Stir together until all ingredients are well combined.
Pour 1/2 cup of whole milk and set aside.
Add half of your dry ingredient mixture to the creamed butter mixture and mix on medium speed until well combined. Then add half of the 1/2 cup whole milk to the muffin batter mixture and mix on medium speed until well combined. You will need to repeat this step one more time so that all of your dry ingredients and whole milk have been added to the muffin batter and everything is well combined.
Now that the muffin batter is complete, it is time to add the star of this recipe, blueberries! Grab a flexible silicone spatula, pour 2 1/2 cups of blueberries into the muffin batter, and gently fold in the blueberries until they are evenly combined within the muffin batter.
Add muffin liners to a twelve-count muffin pan and fill each muffin liner with the blueberry muffin batter. I use a large cookie scoop to add my muffin batter to the muffin liners, however, a table spoon will also get the job done!
Before popping the muffins in the oven, I lightly sprinkle some ground cinnamon, as well as generously sprinkle brown sugar, and granulated sugar over the top of each muffin. You can add as much or as little as you want. Have fun with it!
Pop your muffins in a 350-degree oven and bake them for 30 minutes. The kitchen will begin to smell so good when they are closer to being fully baked.
Let your muffins cool for 15 minutes before eating them and then enjoy!