8-Layer Orange-Scented Smith Island Cake

Directions

1. For the cake batter:
2. Preheat the oven to 350°F. Coat two to four 9-inch round cake pans (depending on how many you have) with cooking spray, then line the bottom of each pan with a round of parchment paper and lightly spray the paper.
3. Combine the flour, 2 cups (400 g) of the sugar, the baking powder, salt and baking soda in a medium bowl. Vigorously stir with a balloon whisk until the ingredients are well distributed. In a separate bowl, combine the butter, oil, milk, orange zest, juice, vanilla, and the 8 egg yolks. Using a whisk, vigorously stir the wet ingredients together until they are uniform in colo
4. Place the 4 egg whites and the cream of tartar in the bowl of a stand mixer fitted with the whisk attachment. Beat on high speed until soft peaks start to form and the egg whites are opaque. With the mixer still on, sprinkle the remaining 1⁄3 cup (67 g) sugar into the egg whites, continuing to beat until the sugar is incorporated and the egg whites are glossy white. Scoop the egg whites out into a separate bowl.
5. Add the dry ingredients to the stand mixer bowl (no need to wash it). With the whisk attachment still on the mixer, start to mix the dry ingredients on low speed. Drizzle the wet ingredients into the bowl, increasing the speed slightly to medium-low as more liquid is poured in. Once all the liquid is added, stop the mixer, scrape down the sides of the bowl and the whisk with a spatula to make sure there aren’t any dry spots, then mix for another 15 seconds, or until the batter is well mixed
6. Remove the bowl from the mixer and scoop about one-third of the egg whites into the batter. Fold in the egg whites with a large flexible spatula. Once incorporated, add the rest of the egg whites in two more batches, folding to incorporate after each addition.
7. Measure out 1 cup of the batter (about 200 g) and spread the batter in a thin layer in the bottom of one of the prepared pans, using an offset spatula if you have one, or the back of a spoon or butter knife if you don’t. Repeat with the second cake pan (and the additional pans, if using). Bake until the edges of the cake are golden brown and the center springs back when you touch it, 9 to 10 minutes. Let cool in the pan for 5 minutes, then run a thin butter knife around the edge of the pan and invert the cake onto a wire rack. Carefully peel off the parchment paper and discard. No need to invert the cake layers; just let them cool upside down.
8. Wipe the edges of the pan with a damp paper towel, scraping off any brown bits from the cake. Spray each cake pan again with cooking spray, line it with parchment paper, and lightly spray the parchment as before. Fill the pans with another 1 cup of batter and bake for 9 to 10 minutes. Repeat as needed for a total of 8 cake layers. Let all the layers cool completely before assembling (the cake layers are so thin that this shouldn’t take long).
9. Alternative: Replace the milk and orange juice in the cake with 1 1⁄3 cups buttermilk and omit the orange zest. Use vegetable oil in place of the olive oil. Make, bake, and assemble as instructed.

1. For the chocolate fudge frosting:
2. Chop the chocolate into 1⁄4-inch chunks. Place in a large microwave-safe bowl and microwave for 30 seconds. Stir and then microwave for another 30 seconds. The chocolate will still be mostly solid but warmed up and the chocolate touching the sides of the bowl should be melty. Place the cream, sugar, vanilla, and salt in a medium saucepan and heat until the sugar has dissolved and the cream is on the verge of boiling. Pour the hot cream over the chocolate and stir with a whisk until all the chocolate has melted and it is smooth.
3. Add the butter, about 2 tablespoons at a time, stirring with the whisk to melt the butter after each addition. Once all the butter has been added and melted in and the chocolate frosting is shiny and smooth, cover the bowl and refrigerate for 1 hour. If the frosting becomes too stiff to spread, let it sit at room temperature for 5 to 10 minutes, then stir with a whisk before using.
4. Once the cake layers are cool, assemble the cake by placing one layer on a cake platter or stand. Add about 1⁄4 cup frosting and spread it to the edges of the cake. Place another cake layer on top of the frosting and repeat until you have all8 layers stacked with frosting in between. Frost the top and sides with the remaining frosting. Let sit at room temperature for 1 hour to set, then serve.