Preheat oven to 350F (175C) and prepare two 8" round cake pans by lining the bottoms with parchment paper and lightly greasing and flouring the sides. Set aside.
In a large mixing bowl (or the bowl of a stand mixer fitted with the paddle attachment) stir together flour, sugars, cocoa powder, baking soda, and salt until well combined.
1 ⅔ cup all-purpose flour, 1 cup light brown sugar, 1 cup granulated sugar, ¾ cup natural cocoa powder, 1 ½ teaspoons baking soda, ¾ teaspoon salt
Add melted butter and oil, stir well. Batter may be thick, this is fine, just stir until all of the dry ingredients are moistened.
½ cup unsalted butter, ½ cup neutral cooking oil
Add eggs, egg yolk, and vanilla extract and stir until well combined. Pause occasionally to scrape sides and bottom of bowl.
Add hot coffee or water, stirring carefully until ingredients are well-combined (be sure to scrape sides and bottom of bowl to ensure batter is uniform).
½ cup hot coffee or hot water
Evenly divide batter between prepared pans. Transfer to center rack of 350F (175C) and bake for 35-40 minutes or until a toothpick inserted in center comes out clean or with moist crumbs.
Allow to cool for 15 minutes before inverting onto cooling rack to cool completely before frosting with your favorite frosting (I recommend the one linked in the recipe above, or one of my favorites linked in the notes below!).
1 batch chocolate frosting
Video
Notes
Frosting
In the video I used my favorite chocolate frosting (linked in the recipe card) but for the photos in this post I used my chocolate fudge frosting (I love both of these options!). Here are some other frostings that work really well with this cake:
Store in an airtight container at room temperature for up to 3 days or in the refrigerator for up to 5 days.
Freezing
You can freeze the completely cooled layers by wrapping them very well with plastic wrap and then freezing.You can also freeze the fully frosted cake. To do this, place your cake in the freezer for about 10-15 minutes or until the frosting is firm. Remove it, wrap very well with plastic wrap, and freeze for up to a month.
Different sized pans
Two 9" pans: Cakes will need to bake for less time, start checking at 27-30 minutes. Please keep in mind that if your pans are dark-colored the cake may need less time to bake.Three 8" pans: Bake approximately 23-26 minutes.Three 9" pans. Cake layers will be quite thin. Bake approximately 20-23 minutes.
Cupcakes
You'll get about 24 cupcakes, evenly divide into two lined 12-count cupcake tins and bake for 17-18 minutes or until a toothpick inserted in the center comes out clean.
Gluten-free
Readers have commented that they have successfully made this recipe by substituting Bob's Red Mill 1:1 baking flour for the flour called for in this recipe.