6-Layer Neapolitan Macaron Delight Cake

Make the Buttercream:

1. Wipe the bowl of an electric mixer with paper towel and lemon juice, to remove any trace of grease. Add egg whites and sugar, and simmer over a pot of water (not boiling), whisking constantly but gently, until temperature reaches 125°F, or if you don't have a candy thermometer, until the sugar has completely dissolved and the egg whites are hot.
2. Place bowl back on mixer and fit with whisk attachment. Whip until the meringue is thick, glossy, and the bottom of the bowl feels neutral to the touch (this can take up to 15 minutes, or longer). Switch over to paddle attachment and, with mixer on low speed, add softened butter in chunks until incorporated, and mix until it has reached a silky smooth texture (if curdles, keep mixing and it will come back to smooth).
3. Add vanilla and salt, continuing to beat on low speed until well combined. Keep in airtight container at room temperature for up to 1 day, refrigerated for up to 7 days, or frozen for up to 2 months.

Make the strawberry macarons:

1. Line two baking sheets with parchment paper or silicon baking mats. Fit a large pastry bag with a large plain round tip, such as #1A.
2. Into a medium bowl, use a fine mesh sieve to sift the almond flour, confectioners' sugar, and salt, twice. It might take a little effort to push through the larger bits of almond flour, for which you can use a wooden spoon. Discard any bits that won't fit through the sieve.
3. Wipe a stainless steel bowl and whisk attachment with lemon juice to eliminate any grease (or beaters and bowl if you are using a hand mixer). Whisk the egg whites on low speed until frothy, about 30 seconds. Increase the speed to medium and add the superfine sugar one tablespoon at a time. Increase mixer speed to medium-high and beat until stiff peaks form, about 3 minutes Add a drop or two of pink color and the flavor oil to the meringue and beat until combined, about 20 seconds.
4. Add one-third of the dry mixture to the meringue and fold in with a rubber spatula, but working deflate the meringue at the same time. It should take about 15 stirs/folds (strokes) before the dry ingredients have been incorporated. Add the remaining dry mixture to the bowl and fold/stir/deflate in the same manner until the batter "flows like magma," about 25 more strokes.
5. Fill the pastry bag two-thirds full with the mixture and pipe 1-inch circles about 2-inches apart on each tray. Lift and drop the trays firmly on the counter a few times to rid of air bubbles.
6. Preheat the oven to 300°F. Let the piped macarons sit while the oven preheats. Bake one tray at a time in the middle of the oven for 15 minutes. Let cool on trays. When completely cool, carefully peel the macarons off of the paper/silicone mat. If you find they are sticking even slightly, use a thin metal spatula to pry them off.

Make the Chocolate Macarons:

1. Repeat the steps for the Strawberry Macarons, but omit the strawberry flavor oil and pink color, and sift 3 tablespoons of dark cocoa powder along with the dry ingredients.

Assemble the Neapolitan Macarons:

1. Pair one of each strawberry and chocolate macaron with the closest in size and pipe a dollop of the vanilla buttercream on the flat side of each chocolate macaron. Sandwich each one with the strawberry macaron. Reserve the "best" macarons that are the most uniform for the top (8-10). For best results, let macarons sit in an airtight container in the fridge for at least a day. Bring macarons to room temperature when ready to use/eat.

Make the Ganache:

1. Place the chocolate in a medium saucepan or bowl with tall sides. In a medium saucepan over medium heat, heat the cream, corn syrup, and salt just until the edges start to bubble (watch carefully, as it's easy to scold the cream). Remove from the heat and pour the mixture over the chocolate. Let sit for 1 minute and then use an immersion blender to combine the mixture until glossy and smooth. Add the butter and vanilla and blend until well incorporated. Let sit at room temperature until spreadable, about 2 hours. Refrigerate for up until 5 days. Bring to room temperature on counter, or microwave in 10-second increments until desired consistency is reached.

Make the Cake:

1. Preheat oven to 350° F. Grease three 7-inch round cake pans and line the bottom with parchment.
2. In a stand mixer fitted with the paddle attachment, beat the butter, brown sugar and vanilla on medium-high speed until lighter in color and slightly increased in volume, about 8 minutes. Lower the speed to medium and add the eggs, one at a time, mixing until each is fully incorporated before adding the next.
3. Sift the flour, cocoa powder, baking soda and baking powder into a medium bowl. Add the salt to the dry ingredients after sifting, and whisk dry ingredients.
4. Alternate dry ingredients and buttermilk into creamed mixture, beginning and ending with dry ingredients. Mix until just incorporated, or finish by hand gently.
5. Divide the batter evenly between the prepared pans. If possible, weigh the batter in each cake pan (about 450 grams per pan, excluding the pans--you will want to tare the scale each time.) This ensures even layers. Smooth with small offset palette knife, and bake until a toothpick inserted in the centre of the cake comes out with only a few crumbs, about 25 minutes.
6. Let pans cool on wire rack for 20 minutes, then invert cakes onto racks, gently, peeling away parchment rounds. Let cool completely.

Assemble the 6-Layer Neapolitan Macaron Delight Cake

1. Spread a small dollop of buttercream onto an 7-inch round cake board. Cut your 3 cake layers each once horizontally with a long, serrated knife, so you have a total of 6 thin layers.
2. Transfer about 2 cups of buttercream to a medium bowl and stir in the strawberry preserves and a drop or two of pink gel paste color.
3. Place your first layer face-up on the board (or plate) and spread one-fifth of the ganache using a small offset spatula, leaving about 1/2" around the edge. With a clean offset spatula, spread about one half of the strawberry buttercream on top. Place another cake layer to top, face-up, and spread another fifth of the ganache on top, followed by a layer of macarons. Press the macarons gently into the ganache.
4. Place another layer on top and spread more ganache, followed by about 1 cup of the vanilla buttercream. Place the next layer on top and spread more ganache, followed by another layer of macarons, gently pushing them into place.
5. Place the next layer on top and spread the remaining ganache followed by the strawberry buttercream. Place the final layer on top, face-down. Wrap the cake in plastic wrap and use your hands to wiggle and straighten the cake into place, if necessary. Refrigerate for at least 30 minutes.
6. In a medium microwave-safe bowl or measuring cup, melt the 10 ounces of dark chocolate in small increments, about 90 seconds total. Once the melted chocolate cools slightly add it to the remaining buttercream and beat to combine.
7. Remove the cake from the fridge and place on cake turntable, if using. Frost the entire outside of cake with a thin layer of the chocolate buttercream to seal in crumbs. Chill until firm, about 30 minutes. Repeat with another layer of frosting, this time working to get the frosting as smooth as possible. Chill again until firm, about another 30-60 minutes.

Make the Glaze: In a small bowl, whisk the confectioners' sugar and milk. Add the color until desired shade of pink is achieved.

1. Use a small offset spatula to spread the glaze over the top of the cake, pushing it slightly over the edges to allow the glaze to drip down the sides. Top the cake with 8-10 neapolitan macarons, pushing them gently into the glaze to secure. Add Pink or Chocolate Crunchy Sprinkles, a bright colourful Sprinkle Medley link Flamingo, or other decorations of choice, if desired.
2. You did it! Hooray! Serve cake at room temperature, but keep refrigerated if not serving the day it's made. Cake will keep for up to 3 days. Bring to room temperature several hours before serving.