Preheat the oven to 350 degrees. Line the bases of three 9-inch cake pans with wax paper. Spray the inside of the pans with cooking oil.
Break the chocolate into pieces and melt using the 1/2 cups of boiling hot water. Allow to cool.
In a large mixing bowl, use a whisk to cream the butter and sugar.
Separate the eggs and set the whites aside for later. One at a time, add the egg yolks to the butter and sugar mixture, beating well.
Blend in the vanilla extract and melted chocolate.
Sift flour with salt and baking soda.
Add alternately flour mixture and buttermilk to chocolate mix. Beat after each addition until smooth.
Beat the eggs whites. Fold them in to the mixture.
Bake in the oven for 30 to 35 minutes. Insert a toothpick into the cake, if it comes out clean, it’s done.
Let the cake cool for 30 minutes and then take it out of the pans. Set aside until completely cooled.