Heat the oven to 350°. Line four 4-inch baking pans with parchment paper and then spray with nonstick baking spray. In the bowl of a stand mixer fitted with the paddle, cream the butter with both of the sugars on medium-high speed for 3 minutes until light and fluffy. Scrape down the sides of the bowl, add the eggs, one at a time, beating on medium-high for 1 minute after each addition. After adding the last egg beat on high for 4 more minutes. Scrape sides of the bowl. Reduce the mixer speed to low, and slowly drizzle in the buttermilk, oil, and vanilla. It should take approximately 3 minutes to add the liquids. Increase the mixer speed to medium-high, and beat until the batter doubles in volume and turns white, 3 more minutes.