Line 2 baking sheets with either parchment paper or silicone mats and fit a large piping bag with a round decorating tip (like the Wilton 2A). Set to the side.
Weigh all your ingredients using a food scale.
Sift the almond flour and Domino® Powdered Sugar together twice, removing any bits left behind from the sifter. Whisk together once more to fully blend (or use a food processor).
Using a double boiler, heat the Domino® Golden Sugar and egg whites over 1 - 1.5 inches of simmering water, continually whisking until the sugar has fully dissolved and the mixture is frothy in appearance (about 5-6 minutes). Test by rubbing a little of the mixture between your pointer finger and thumb to make sure all sugar granules have dissolved.
Transfer the hot mixture to a mixing bowl of a stand mixer fitted with the whisk attachment and set the speed to high. When the mixture initially reaches the soft peaks stage, add in the vanilla extract. Continue to mix on high speed right until stiff peaks form (about 10 minutes). The meringue should look glossy and be able to hold its shape when you invert the whisk attachment. Add in the 2-3 drops of blue food coloring and mix until fully blended.
While your meringue is forming, add 1 drop of brown food coloring to a small bowl. If you’re using a thick food coloring or prefer a lighter brown color for your macarons, add ¼ teaspoon of vanilla extract to thin it out a little. Set to the side.
Using a spatula, gently fold in half of the dry ingredients with the stiff meringue. Folding until most of the dry ingredients have mixed in with the meringue. Add in the remaining dry ingredients.
As you continue to fold, press the batter against the side of the bowl. Keep folding until the batter is the consistency of lava. If the batter falls off the spatula in ribbons (or can make a figure 8 pattern) without breaking, it's time to pipe. If not, fold 2-3 more times, then test again.
When ready, carefully scoop the batter into the prepared piping bag. Holding your bag perpendicular to the silicone mat (or parchment paper), pipe out a circles close to 1.5 inches in diameter. When you bang the baking sheets on the counter after piping they should spread out just a little.
Gently bang your baking sheets on the counter 3-4 times to release the air bubbles. Use a toothpick to carefully remove them.
Dip a small brush into the bowl of brown food coloring vanilla extract mixture. Holding your brush roughly 6-8 inches over top of the macarons, gently tap the brush with your pointer finger to release specks of the food coloring over each macaron.
Set the trays of robin’s egg macaron shells to the side, somewhere cool and dry, where they can rest/dry for 40 minutes. The macarons are ready to be baked when the tops are dry to the touch and no longer sticky. Use a ceiling fan to help dry them, if you have one. Drying times will vary based on where you live. The higher the humidity, the longer the rest time.
When you're close to the end of the resting time, preheat your oven to 300ºF and place your oven rack on the 2nd level mark (just above the center).
Bake only 1 tray of the macarons at a time for 14 minutes at 300ºF, rotating the baking sheet at the 7 minute mark. Do not skip this step. And other then opening the oven door to rotate the macarons, do not open it while baking.
When done, remove the macarons from the oven and allow to cool for 10-15 minutes. If your shells are still a little sticky after this time frame, you can either continue to let them cool at room temperature or pop them in the freezer for 15-20 minutes.
If not making/piping the frosting until the next day, keep the macaron shells stored in an airtight container either in the freezer or refrigerator.
Add the coconut flakes to a small skillet and heat over low-medium heat. Continue to stir as it heats up and the flakes begin to turn a golden brown color. About 4-5 minutes. Remove from heat and spread out onto a plate to cool. If making in advance, keep the toasted coconut flakes stored in an airtight container at room temperature until ready to use.
Using your hand mixer or stand mixer fitted with a paddle attachment, mix together the unsalted butter, sifted Domino® powdered sugar, unsweetened cocoa powder, salt, light corn syrup, vanilla extract, and melted milk chocolate over low speed until full blended and smooth. Use a spatula to scrape down the sides of the bowl as needed.
Fit a small- to medium-size piping bag with a coupler and small decorating tip, then fill the bag with ¾ of the frosting.
Pipe a circle of the milk chocolate frosting onto a macaron shell, add a little of the toasted coconut flakes to the center, then gently press another macaron shell on top. Repeat until you have used all the macaron shells. Store any leftover frosting in the refrigerator for up to 1 week.
Keep the robin’s egg macarons stored in an airtight container in the refrigerator. Macarons taste their very best after 2-3 days of sitting in the refrigerator.