Preheat oven to 425F degrees. Spray your muffin tin of choice with non-stick spray or line with muffin liners. Set aside.

In a large bowl, gently toss together flour, baking powder, salt, and cinnamon. Mix until all dry ingredients are combined - a 20 second toss to disperse everything together. Set aside.

In a medium bowl, whisk together eggs and sugar until combined. Mix in milk, oil, and vanilla. Mixture will be pale and yellow. Fold wet ingredients into dry ingredients and mix everything together by hand. Avoid overmixing.

Gently mix until all the flour is off the bottom of the bowl and no big pockets of flour remain. The batter will be VERY thick and somewhat lumpy. Fold in the blueberries.

Pour batter into prepared muffin tins, filling all the way to the top. Top with a sprinkle course sugar, if preferred. Bake at 425F degrees for 5 minutes. Reduce oven temperature to 375 and continue to bake for 25 minutes until tops are lightly golden and centers appear set.

Allow to cool for 10 minutes in pan before enjoying.