Boil the water in a sauce pan. Move from heat, add in cocoa powder whisking with a hand whisk constantly until the cocoa is melted. You might need to put it back in the burner for a minute. It's easy to burn, so watch closely. Remove from heat and set aside.
Sift together the dry ingredients (flour, salt, baking soda, sugar) in a mixing bowl.
Add liquid ingredients (eggs, oil, buttermilk) into a separate bowl. I add them in a liquid measuring cup.
Add the wet ingredients to the dry while mixer is on medium. Mix until combined.
Scrape in the melted chocolate and mix until combined.
Pour the batter evenly into two oiled 8 inch round cake pans. Line with parchment paper if you want.
Bake in a 325 degree oven for 20-25 minutes until the cake is not jiggly in the center.
Let the cakes cool while you make the chocolate frosting.