Preheat the oven to 350°F.

Spray two 8- or 9-inch round cake pans liberally with nonstick cooking spray. Set aside.

Place the butter, canola oil, granulated sugar, brown sugar, and vanilla into a large mixing bowl. Using a hand mixer or stand mixer fitted with a whisk attachment, cream ingredients together on medium speed until smooth, about 1 minute, scraping sides of bowl with rubber spatula as necessary. Add the eggs, and continue to beat until mixture is light and fluffy, about 1 minute.

Sift the flour, cocoa powder, baking soda, and salt through a fine-mesh sieve into the bowl. Beat mixture on low until ingredients begin to come together. Slowly stream in the buttermilk and food coloring and continue mixing, scraping the sides of bowl with a rubber spatula as needed, until a smooth, vibrant batter forms. Pour batter into the prepared cake pans, dividing it evenly between them.

Bake the cakes on middle rack of oven until a toothpick inserted in the center comes out clean, 28-33 minutes.

Check to see that cakes are done. Remove from oven or add time as needed.

Allow the cakes to cool in pans for 15-20 minutes. To release a cake, run a butter knife between edge of the cake and pan. Turn each cake onto a cooling rack. Allow to cool for 1-2 hours before frosting and serving.

While cakes cool, make the frosting. Place the cream cheese and butter in a large mixing bowl. Beat with a mixer on medium speed until smooth and creamy.

Add the powdered sugar in two additions, beating on low speed after each until sugar is fully incorporated into the cream cheese mixture. Add the vanilla extract and salt to bowl. Continue beating on medium-high speed until frosting is light and fluffy, 2-3 minutes.

Frost and assemble the cake as desired. Refrigerate until ready to serve.