About an hour before starting the cake, set cream cheese and eggs out to come to room temperature.
Preheat oven to 325°F.
In a medium bowl, sift together the flour, baking powder, and salt.
In a stand mixer fitted with a paddle attachment, cream the sugar and cream cheese on a medium speed. Slowly add the grapeseed oil, about ¼ cup at a time. Mix well after each addition of oil to avoid oil splashing all over the kitchen! Beat for 3-4 minutes, until the mixture no longer pulls away from the side of the bowl and all of the oil is fully incorporated.
Add the eggs to the batter, one at a time, mixing well after each addition and scraping the sides of the bowl as needed. Add vanilla and caramel extract (if using). Beat for 1-2 more minutes.
Add about 1/3 of the flour mixture and mix on the lowest setting. With the mixer still on low, add half of the buttermilk, followed by another 1/3 of flour mixture. Finish by adding the last half of buttermilk and the last 1/3 of flour mixture. Mix until combined, being sure to scrape the sides and bottom of the bowl.
Distribute the batter between the three cake pans (it will go right on top of the Biscoff cookie crust).
Bake for 27-32 minutes. Check for doneness by inserting a toothpick into the middle of the cake. It will come out with a couple small crumbs stuck to it when the cakes are fully baked.
Let cool for 10-15 minutes, or until cool enough to handle, before turning the cakes out onto a cooling rack. Cool completely and cover with plastic wrap. Place each layer on a flat surface in the freezer until it’s time to assemble the cake.