Preheat your oven to 350 degrees F. Spray three 8-inch round cake pans with non-stick spray, line the bottom of each pan with parchment paper and spray again. Set aside.
In a medium size bowl, stir together the cake flour, salt and baking powder. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, canola oil, and sugar on high until light and fluffy, about 5 minutes.
Add the eggs and egg yolks, one at a time to the bowl and beat on medium until well incorporated.
Turn the mixer on low and add half of the flour mixture to the butter mixture until fully incorporated. Then the sour cream and blend well. Finish by adding the remaining flour mixture and mix until combined.
Add the clear vanilla extract and butter extract and beat on low until incorporated. Scrape down the sides of the bowl and mix on low for another 30 seconds.
Evenly distribute the cake batter among the three pans and bake for about 23-28 minutes or until a toothpick inserted into the middle of the cakes comes out with just a few moist crumbs.
Remove cakes from the oven and let cool in pans for 10 minutes before inverting onto cooling racks to cool completely.