Once the cake has been made and cooled, carefully remove from the pans.
Make the buttercream. Separate the batch into two bowls. Approximately ⅔ in one large bowl and the other ⅓ in a smaller bowl. Tint the larger bowl with the light blue food coloring - start with just one or two drops and add more if
needed. Stir well. Add the ¼ c. cocoa powder to the smaller bowl. You may need a dash of milk if the added dry ingredients make the mixture too stiff. Place the chocolate buttercream in a pastry bag fitted with a 2D decorating tip. Set aside.
With the cake removed from the pans, cut off a layer from the very top to ensure a level cake with a serrated knife.
Place one cake round on a plate or platter of your choice. Place approximately ½ cup of blue frosting and spread to cover the top of the cake.
Place the second cake round on top of that frosting and cover with additional frosting. Continue to spread the frosting down the sides and spread as evenly as possible - this is just the crumb coating, so just a thin layer is sufficient to set the cake.
Once an even, thin layer coats the cake side and top, place in the fridge or freezer to chill for approximately 30 minutes.
Remove the cake from the fridge/freezer and coat with another, thicker layer of blue frosting. Even it out as best as possible, preferably with an angled metal
spatula or flat edge scraper.
You can use a piece of parchment paper to smooth any ridges and divots in the frosting by lightly pressing the parchment on the cake. Move around as needed to smooth areas that are stubborn until the blue buttercream is smooth.
Sprinkle with just enough cocoa powder to give a “splatter” look. Start with just a little bit, you can always sprinkle a little bit more but adding too much is very
difficult to remove without compromising the smoothness of the frosting.
Press a handful of chocolate shavings around the bottom of the cake. Continue all the way around - some will drop onto the platter, spread around evenly.
Using the pastry bag with the chocolate frosting fitted with the 2D tip, decorate the cupcakes.
Start in the center of the cupcake and with slow, steady pressure with the tip perpendicular to the top of the cupcake, rotate the frosting in a spiral pattern all the way around the center point and out toward the edge of the cupcake.
Stop applying pressure to the pastry bag and slowly break away from decorating the cupcake. Place three of the robin egg chocolate candies in the middle of the nest of the cupcake. Repeat with remaining cupcakes.
To decorate the cake with chocolate frosting: Using the same spiral motion to decorate the cupcakes, create the chocolate nests around the exterior edge of the cake.
Place the chocolate candies in the center of each chocolate nest. Top with remaining chocolate shavings, if desired.
Store in the fridge until ready to serve.