Preheat your oven to 325 degrees.
In a medium mixing bowl, whisk together the flour, baking powder and salt. Set aside.
In the bowl of a stand mixer, beat the grapeseed oil, cream cheese and sugar on medium-high speed for 2-3 minutes.
With the mixer on medium, add the eggs, one at a time, making sure to scrape down the sides and bottom of the bowl between each addition. Once all of the eggs are added, turn the mixer to mediump-high speed and beat for an additional 2 miniutes.
With the mixer on low, alternately add the flour mixture and the buttermilk in three additions, starting and finishing with the flour. Combine until incorporated, about 20 to 30 seconds.
Evenly distribute the batter among the three cake pans on top of the crusts (about 15-16 ounces of batter in each pan) and bake for 30 to 35 minutes or until a toothpick inserted in the center of the cake comes out with just a few moist crumbs.
Let cool in pans 5-10 minutes before inverting onto a wire rack to cool completely. Once cooled, you can cover with plastic wrap and store in your refrigerator overnight or freezer for longer.