Pre-heat oven to 350 degrees. Grease three 8 inch round cake pans.
In a stand mixer fitter with a paddle attachment, mix together the flour, baking powder, sugar, and salt.
With the mixer on low speed, mix in the butter small pieces at a time. Continue to mix until the mixture become crumbly. Continue mixing on low and add in the eggs white until just combined and then add in the butter milk, two parts at a time.
Scape the sides of the bowl and then add in the vanilla and oil until fully incorporated.
Remove the mixer from the stand and fold in the frozen berries.
Divide the batter evenly between the three pans. tap the pans on the counter to get out any air bubble and to even out the batter.
Bake for approximately 35 minutes or until a tooth pick comes out clean. Let cool in the pan before removing.