Preheat oven to 350 degrees. Prepare three 6" pans with non-stick cooking spray and parchment.
In a bowl with an electric mixer fitted with a paddle attachment, combine flour, sugar, baking powder and cinnamon on a low speed.
Add butter and milk. Mix on a low speed until just combined. Increase to medium speed and mix for 1-2 minutes.
Scrape down the sides of the bowl and add eggs and vanilla extract. Beat on medium speed until it is just combined.
Divide evenly between the three cake pans.
Bake for 16-18 minutes, or until wooden toothpick comes out clean.
Set pans on wire rack to cool.
Once it is cool, take the cakes out of their pans and level them with a serrated knife.