1. Make the Chocolate Cake Layers:

• Preheat oven to 350°F (175°C). Grease three 6-inch round cake pans. Dust the insides with cocoa powder (tapping out excess). Line the bottoms with parchment paper circles.
• In the bowl of a stand mixer fitted with the paddle attachment, combine the flour, sugar, cocoa powder(s), baking soda, baking powder, and salt. Mix on low speed until well combined.
• In a separate medium bowl, whisk together the eggs, oil, buttermilk, and vanilla extract.
• With the mixer on low, slowly pour the very hot water into the wet ingredients while whisking constantly (this tempers the eggs slightly).
• Add the combined wet ingredients (including the hot water mixture) to the dry ingredients in the mixer bowl. Mix on medium speed for 2-3 minutes until the batter is smooth. Scrape down the bowl as needed. Batter will be very thin.
• Pour the batter evenly into the three prepared pans.
• Bake for approximately 30-35 minutes, or until a toothpick inserted into the center comes out mostly clean (a few moist crumbs are okay).
• Place the cakes on a wire rack to cool in the pans for 10 minutes.
• Carefully invert the cakes onto the wire rack, remove the parchment paper, and let them cool completely.

2. Make the Honeycomb Candy:

• Prepare Pan: Line a quarter sheet pan (9” x 13”) with a silicone baking mat OR line it with foil and grease the foil well with cooking spray. Have your sifted baking soda ready near the stove.
• Cook Sugar Syrup: Place the sugar, corn syrup, and water into a large, heavy-bottomed saucepan. Stir well only until the sugar is dissolved. Do not stir after this point.
• Wash Down Sides: Use a pastry brush dipped in water to wash down any sugar crystals from the sides of the pot.
• Boil to Hard Crack: Bring the mixture to a boil over high heat. Clip on a candy thermometer. Cook, without stirring, until the temperature reaches 300°F (149°C – Hard Crack Stage). This will take about 10 minutes. Watch carefully as the temperature rises quickly near the end.
• Add Baking Soda: Immediately remove the saucepan from the heat. Sprinkle the sifted baking soda evenly over the top of the hot syrup. Quickly and briefly whisk it in – just enough to incorporate (MAX 5 seconds). The mixture will foam up dramatically and turn golden. Do not over-whisk, or it will deflate.
• Pour and Cool: Immediately pour the foaming mixture into the prepared lined pan. Do not spread it. Allow it to cool completely and harden at room temperature (1-2 hours). Do not refrigerate.

3. Prepare Honeycomb for Cake:

• Once the honeycomb is completely cool and hard, carefully lift it from the pan (using the mat or foil).
• Use the tip of a knife or gently break it with your hands into large, decorative shards for the top of the cake. Set these aside.
• Chop up some of the remaining honeycomb into small, pea-sized pieces to be used between the cake layers.
• Store all honeycomb pieces immediately in an airtight container, separated by parchment paper if layering, at room temperature. Honeycomb absorbs moisture quickly and will become sticky if exposed to air.

4. Make the Chocolate Frosting:

• In a medium bowl, whisk the sifted powdered sugar and sifted cocoa powder(s) together to combine.
• In the bowl of a stand mixer fitted with the paddle attachment, beat the room temperature butter on medium-high speed until smooth and creamy, about 1 minute.
• Reduce speed to low. Add the sugar/cocoa mixture about 1 cup at a time, mixing until just combined after each addition. Scrape down the bowl.
• Beat in the melted and slightly cooled dark chocolate until combined.
• Add 1 tablespoon of heavy cream and beat until combined. Add more cream, 1 tablespoon at a time, only if needed to reach a smooth, spreadable consistency.
• Increase speed to medium-high and beat for approximately 5 minutes until the frosting is very smooth and fluffy.

5. Assemble the Cake:

• If necessary, level the tops of the cooled cake layers. Place one layer onto your cake stand or serving plate.
• Top with approximately 2/3 cup of the chocolate frosting and spread evenly.
• Sprinkle some of the crushed (small pieces) honeycomb evenly over the frosting.
• Place the second cake layer on top, spread with another 2/3 cup frosting, and sprinkle with more crushed honeycomb.
• Place the third cake layer on top.
• Apply a thin “crumb coat” of frosting over the entire cake. Refrigerate for 30 minutes to set the crumbs.

6. Frost and Decorate:

• Frost the top and sides of the chilled cake smoothly or with a rustic pattern using the remaining frosting.
• Carefully arrange the large honeycomb shards decoratively along the top edge or center of the cake just before serving (honeycomb can get sticky if placed on the cake too far in advance).