Preheat oven to 350 degrees F.
Combine the oil, sour cream, eggs, sugar, vanilla, zest, and buttermilk in a stand mixer or in a bowl with an electric hand mixer.
Mix well until eggs are fully incorporated. Scrape the bowl if necessary.
Combine the cake flour, soda, powder, and salt in a bowl. Add to the wet and mix until just combined.
Distribute the cake mix equally between two greased 8 inch cake pans. Bake for about 40-50 minutes, until a toothpick comes out clean. Check at the 40 minute mark to be sure not to overbake them.
Allow to cool enough to handle, then remove from cake pans and allow to fully cool on a wire rack.
"Tort" the cakes by carefully slicing each layer into two thinner layers (optional!). Wrap them in plastic wrap and place in the freezer.