Generously butter two 6-by-3-inch regular or contour cake pans and then dust with sifted cocoa powder. Tap out the excess cocoa. I used 9" round cake pans and lined the bottoms with wax paper and then butter and dusted with cocoa powder.
Preheat the oven to 350 degrees F.
In a large mixing bowl, sift together the flour, cocoa powder, baking soda, baking powder, and salt.
Put the chocolate in a large pyrex or heatproof bowl and pour the boiling water over it. Whisk until the chocolate melts, then let the mixture cool for about 15 minutes.
In a small bowl, whisk together the buttermilk and vanilla then set aside.
In the bowl of a stand mixer fitted with the whisk attachment, whisk the eggs on high speed until light and foamy, about 2 minutes. Reduce to low and slowly add in the oil, whisking until combined, about 30 seconds. Raise the speed to medium and whisk until fully incorporated, about 30 seconds longer.
Reduce the speed back to low and slowly pour the cooled chocolate mixture into the egg mixture. Then also slowly add in the buttermilk and vanilla mixture. Finally, add the sugar and whisk until the batter is smooth and liquid, about 2 minutes.
Remove the mixing bowl and add the sifted dry ingredients and fold together until just incorporated. Using a rubber spatula, scrape down the sides of the bowl and mix in. The batter may have lumps, but stop mixing.
Pour the batter through a medium-mesh sieve into a large measuring cup or bowl. Press a rubber spatula against the sides and bottom of the sieve to push through as much batter as possible. Discard the remaining lumps. Pour the batter evenly between the two prepared pans. Bake until a tester inserted in the centers comes out clean, about 45 minutes.
Transfer to wire racks and let cool in the pans for about 20 minutes. When the cakes are just cooled enough to touch, carefully run an offset spatula around the edges of the pans to loosen the cake, then invert them onto the racks and remove the pans.
Let cool for about 20 minutes longer then wrap completely in plastic wrap and refrigerate for a minimum of 1 hour before icing. They may be refridgerated for up to 3 days.
Assembly
Using a 1M or 2D Star Tip, fill with raspberry buttercream frosting. Pipe a small bit to hold the cake in place on your cake stand. Center your bottom cake layer in place with the top side down. Tip your icing bag on a 90 degree angle and pipe all the way around the outside edge of the bottom layer. Then spiral inward to the center, going round and round to make an even layer of icing. Using a small offset spatula, smooth the inside of the icing, leaving the outside edges untouched.
Center and place the second layer on top, right side up. Again, pipe around the outer edge of the top layer then spiral inward until you reach the center. Use an offset spatula to smooth the top icing layer but leaving the edges untouched.
Pipe with a petal tip or buy a small flower to decorate the center if you wish.
Recipe by Just a Smidgen at https://justasmidgen.com/2013/11/18/pretty-pink-tomboy-cake/