1. Preheat the oven to 350 degrees. Grease 8 8-inch round cake pans or as many as you have, using again as needed.
2. Sift together the flour, baking powder and salt.
3. Add the butter and sugar to the bowl of your stand mixer and beat on medium speed until light and fluffy. Add in the eggs, one at a time, mixing until fully incorporated before adding the next one.
4. Reduce the mixer speed to low and sift ½ cup of the flour mixture in, followed by a little bit of the evaporated milk, repeating until both are used, ending with the flour. Finish with the vanilla extract and the water.
5. Fill each cake pan with a scant ⅔ cup of batter, spreading it evenly over the pan. Tap the pans on the counter to release any air bubbles.
6. Bake for 8-9 minutes or until just golden around the edges and starting to pull away from the pan. Repeat with any remaining batter until you have at least 8 layers of cake baked.
7. Allow cakes to cool in their pans. Meanwhile, prepare the icing.
8. Add the butter and cocoa powder to the bowl of a stand mixer. Beat on low speed until combined, then add in the salt.
9. Add in the powdered sugar ½ cup at a time until fully incorporated. Add milk and vanilla extract to thin out the frosting. If it is too thick, add more milk. If it is too thin, add more powdered sugar.
10. Turn out one layer of cake onto a cake stand. Spread ½ cup frosting on top and spread to the edges. Repeat with each layer of cake. Don’t worry if the cake breaks, you won’t be able to tell once it is all together.
11. Spread frosting over the top and down the sides of the cake, using an offset spatula to make it smooth.
12. Using a large serrated knife, slice halfway into the cake and cut a thin wedge. Serve cake on its side to showcase the layers.
13. Refrigerate if you are not serving right away.