Step 1

Prep: Prep: Preheat your oven to 350° F. Prepare three 8-inch cake pans. Use a paper towel to rub shortening all over the inside of each pan, coating them evenly and completely. Cut a piece of parchment paper to fit in the bottom (it doesn't have to be perfect or cover the bottom completely). Place this on top of the greased pan bottom, then grease over the parchment paper as well. Add a handful of flour, and tap the pan around to evenly coat the entire inside with flour, tapping out the excess.

Step 2

Make the Cake Batter: In a 4-cup glass measuring cup or in a medium bowl, add the two cups of hot water (I microwave it for 30-45 seconds, until it's steaming). Whisk in the cocoa powder, then set aside. In a large mixing bowl, whisk together all the dry ingredients, making sure the brown sugar chunks are broken up. Return to the wet ingredients and whisk the oil and vanilla into the measuring cup of hot water and cocoa. Pour this mixture into the dry ingredients, and stir gently until everything is combined and no streaks of flour remain. The batter may have a few small lumps throughout - that's fine - don't try to break them all up!

Step 3

Bake: Divide the batter evenly between your three prepared pans (you'll have about 520 grams of batter per pan). Bake for 10 minutes, then rotate each pan 180 degrees and bake another 10 to 12 minutes. A toothpick inserted into the center will pull out moist crumbs when the cakes are done. Let cakes cool in the pans, placed on cooling racks, for 8 minutes. Then, run a butter knife around the edge to loosen the cakes and invert onto the cooling racks. Let cool completely while you make the frosting.

Step 4

Make the Frosting: In a medium microwave-safe bowl, melt together the semi-sweet chocolate, corn syrup, and water in 30 second intervals, stirring between each interval until completely melted. Set aside to cool to room temperature (you can speed this up in the fridge). In a large bowl, beat the butter on high speed with an electric mixer until creamed, about 1 minute. Beat in the powdered sugar in two additions, using milk as needed to help it come together. Beat in the cocoa powder on low, making sure it's well mixed in. Beat in the room temperature chocolate mixture - it will look a little curdled and weird at first, but it will smooth out to silky perfection after 1-2 minutes of mixing! Beat in the vanilla and salt last.

Step 5

Assemble the Cake: Place one cooled cake layer on your cake plate, and place this on a cake turntable (for ease, no need to run out and buy one). Add 1 and 1/3 cups of frosting and spread it in an even layer. Chill for 5 minutes in the fridge so it doesn't all smoosh out when you add the next layer. Add the next cake layer, and use an offset spatula to seal the two layers together by spreading any frosting peeking out between the layers. Chill for 10-15 minutes, then repeat this. By the time the final layer is on, you'll have a thin crumb coat of frosting around the side of the cake. Let this chill for 15 minutes or so before finishing frosting the top and sides of the cake, swirling the frosting in a rustic manner.

Step 6

Serve & Store: Top with sprinkles if desired, then slice and enjoy! Store leftover cake in the fridge in an airtight container, with plastic wrap pressed over the cut portion to keep it moist. This cake keeps well for 2-4 days in the fridge (not as long as a cake that has eggs/dairy, but it still holds up pretty well!).