Preheat the oven to 350°F.

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

Place the sugar, canola oil, eggs, coffee, sour cream, buttermilk, and vanilla in a large mixing bowl. Whisk until smooth and combined.

Sift the flour, cocoa powder, baking soda, and salt into the bowl. Whisk until the ingredients come together in a smooth batter.

Divide the batter evenly between the prepared cake pans.

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

While the cakes cool, make the frosting. Place the butter and cream cheese 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 the sugar is fully incorporated. Add the vanilla extract, heavy cream, and salt to the bowl. Continue beating on medium-high speed for 2-3 minutes, until the frosting is light and fluffy. Adjust the consistency with an additional tablespoon of heavy cream if the frosting seems too thick.

Frost cake as desired. Refrigerate until ready to serve.