Directions

1. Preheat oven to 350°. Spray 3 (9-inch) cake pans with baking spray with flour; line bottom of pans with parchment paper rounds; spray again and set aside.
2. In a small bowl, combine chocolate and boiling water, whisk until smooth and melted; set aside. In a medium bowl, beat butter with an electric mixer at medium-high speed until creamy, about 2 minutes. Add sugar and beat until light and fluffy, about 3 minutes. Add eggs, one at a time, beating well after each addition.
3. In a separate medium bowl, combine flour and salt. Add baking soda to buttermilk, stirring to dissolve. Reduce mixer speed to low. Alternately add flour mixture and buttermilk to butter mixture, beginning and ending with flour mixture. Add chocolate and vanilla, beating to combine. Divide batter among prepared pans, smoothing the surface. Bake for 30 to 35 minutes, or until a wooden pick inserted near the center comes out clean. Remove from oven and cool in pans for 10 minutes. Remove to wire racks to cool completely for at least 4 hours. Frosting a warm cake may make your frosting turn runny. The only exception is if the recipe explicitly directs you to do so.