Preheat oven to 350 F. Grease and flour 2 9-inch round cake pans.** Set aside.
In a large bowl, whisk the oil and sugars together until combined. It will look like wet sand.
½ cup vegetable oil, 1 cup granulated sugar, 1 cup brown sugar
Whisk in the eggs one at a time.
3 large eggs
Add the sour cream and vanilla, and whisk until combined.
½ cup sour cream, 2 teaspoons pure vanilla extract
Add flour, cocoa powder, baking soda, baking powder and salt, and stir until just combined. Batter will be thick.
2 cups all-purpose flour, ¾ cup unsweetened cocoa powder, 1 ½ teaspoons baking soda, 1 teaspoon baking powder, 1 teaspoon kosher salt
Stir in the warm water just until combined.
1 cup warm water
Divide the batter evenly between the prepared pans.
Bake for 25-35 minutes, or until a toothpick inserted into the center of the cakes comes out with a few fudgy crumbs attached.
Place the pans on a wire cooling rack and let cool for 20 minutes.
Run a thin knife around the edge of each cake to loosen it from the pan, and then invert the cakes onto the rack. I like to lightly spray the cooling rack with nonstick spray to keep the cake from sticking.