Preheat oven to 350°. Either grease a 12-cup muffin tin or place paper liner in each cup.
In a mixing bowl, cream together butter and sugar until smooth. Beat in eggs, then milk and vanilla.
In a separate bowl, mix the two flours, baking powder, salt, and cinnamon. Add the dry ingredients to the wet ingredients and fold together with a rubber spatula.
Add blueberries and fold them in gently.
Divide the batter between muffin cups.
Bake for 25-30 minutes, until puffed and golden. Rotate the muffin tin after 15 minutes to ensure even baking.