Preheat the oven to 325ºF. Lightly grease three 8-inch (20 cm) cake tins with vegetable oil and line with parchment paper.
Whisk the flour, cocoa, baking soda, and salt in a mixing bowl. Set aside.
2 cups all-purpose flour, 1 cup cocoa powder, 1 tablespoon baking soda, 1 ½ teaspoons salt
Add the sugar, vegetable oil, milk, eggs, and vanilla to a mixing bowl. Mix well to combine.
2 cups granulated sugar, 1 cup vegetable oil, 1 cup whole milk, 2 large eggs, 2 teaspoons vanilla extract
Add the flour to the wet mixture and mix on low speed to combine. Stop when only a few streaks of flour remain. Add the boiling water and mix well.
1 cup boiling water
Divide the cake batter evenly between the three prepared cake tins (about 530 grams per cake). Place the tins in the oven and bake for 33 to 35 minutes or until a tester comes out clean.
Remove the tins from the oven and transfer to wire racks. Cool the cakes in the tins for 10 minutes before turning them out directly onto the racks to cool completely.
Make The Coconut Frosting
Mix the butter, shortening, coconut extract, and salt until smooth and creamy. Sift in the powdered sugar. Mix on low to combine. Once the sugar is mixed in, increase the speed to high for one minute.
Use a serrated knife to level the tops of the cakes. Place one cake on a serving plate or platter.
Spread ½ to ¾ cup of icing on the cake top. Place a second cake on top and repeat. Place the third layer on top. Ice the cake with the remaining frosting.
Garnish the cake with toasted coconut, chocolate ganache, or anything else you like before serving.
Notes
For even distribution, use a piping bag to pipe the icing between each layer and on the outside of the cake.