Preheat oven to 350F (177C) and prepare two deep 8" round cake pans** by lining the bottoms with parchment paper and lightly greasing the sides. Set aside.
In the bowl of a stand mixer (or in a large bowl using an electric mixer) cream together the butter, canola oil and sugar until creamy and well-combined.
Add eggs, one at a time, beating well after each addition.
Stir in vanilla extract.
In a separate, medium-sized bowl, whisk together flour, baking powder, and salt.
Using a spatula and gently hand-mixing, alternate adding flour mixture and buttermilk to the butter mixture, starting and ending with flour mixture and mixing until just combined after each addition. The batter should be smooth and completely combined, but avoid over-mixing.
Evenly divide batter into your prepared cake pans, and bake on 350F (175C) for 30-35 minutes. When the cake is done, the surface should spring back to the touch and a toothpick inserted in the center should come out mostly clean with few moist crumbs (no wet batter).
Allow cakes to cool in their cake pans for 10-15 minutes before inverting onto cooling rack to cool completely before frosting.
Frost cake using my chocolate frosting (or see notes for other favorite frosting options) and decorate with sprinkles (if desired).
*You may substitute vegetable oil or another neutral oil instead**You may use 9" cake pans instead, but watch the cooking time as they may need less time in the oven.
The chocolate frosting I linked to in the ingredients is my favorite pairing with this cake, but here are some other great options:
Fill cupcake liners no more than ¾ of the way full. Bake on 350F for 17-18 minutes or until a toothpick inserted in the center comes out with a few moist crumbs or clean. This recipe will make approximately 24 cupcakes.