Robin's Egg Macarons with Chocolate Filling

For the Shell

1. Line two large sheet pans with parchment paper or Silpat mats. Set aside.
2. Place a heatproof bowl over a small saucepan of simmering water. Add the egg whites and granulated sugar to the bowl. Whisk until the sugar has fully dissolved, about 2 minutes.
3. Transfer the mixture to the bowl of a stand mixer fitted with the whisk attachment. Beat the egg whites and sugar on medium-high speed until they form stiff peaks, about 3-4 minutes.
4. Use a fine mesh sieve to sift the powdered sugar and almond flour into the egg whites. Make sure to discard any large lumps; don’t force them through the sieve.
5. Gently fold the dry ingredients into the egg whites by making a "J" shape with your spatula. Make sure to scrape all the way to the bottom of the bowl!
6. Once the dry ingredients have been almost fully incorporated, add the gel food coloring, if using (see notes).
7. Continue folding, this time gently smushing the meringue against the sides of the bowl as you fold. Smush and fold a few times before checking to see if the meringue is at the Figure 8 stage.
8. If you can draw an 8 with the meringue without the stream breaking, it’s ready to pipe. If it falls off in clumps, continue the smush and folding a few more times before trying again.
9. When the meringue flows in smooth ribbons, transfer it to a piping bag fitted with a small round tip (Wilton #10 or 12).
10. Pipe either circles or egg shapes that are about 1 inch in diameter. Once you’ve finished the first tray, hold it a few inches off the counter and drop it straight down to release any air bubbles. Repeat a few times, or until it looks like any large air bubbles have popped.
11. Repeat with the second tray.
12. Set the trays aside to rest for 25-30 minutes, or until they have developed a skin. On humid days, this could take up to an hour. When the macarons are ready to bake, you should be able to touch the macarons gently without the meringue sticking to your finger.
13. While the macarons rest, preheat your oven to 325°F.
14. Bake the macarons, one tray at a time, for 13 minutes. Make sure to turn the tray half way through cooking so the feet rise evenly.
15. Allow the macarons to cool fully on the tray. Trying to remove the macarons while they’re warm may result in sticking.

For the Filling

1. Microwave the chocolate chips for 1 minute and set aside to cool for a few minutes.
2. Add the butter to the bowl of a stand mixer fitted with the paddle attachment. Beat on medium speed until the butter has become light and airy.
3. Turn the mixer to low speed and slowly add the powdered sugar, followed by the melted chocolate. If the mixture looks dry, add a tablespoon of milk or cream.
4. When all of the ingredients have been incorporated, turn the mixer to medium-high speed and whip until the buttercream becomes light and fluffy, about 2-3 minutes. Make sure to scrape down the sides of the bowl a few times.
5. Transfer the buttercream to a piping bag fitted with your choice of tip. Set aside until ready to use.

Assemble and Age

1. Place the macarons in similar-sized pairs. Pipe a small dollop of icing onto one macaron and place the second shell on top. Press down gently, just until the filling reaches the edges.
2. To make the macarons speckled, combine 1 teaspoon of water with a few drops of black food coloring. Dip a pastry brush in the coloring and then rub it against the back of a fork to drip the paint onto the macarons (make sure not to get it on your clothes; it will stain).
3. Allow the food coloring to dry completely before transferring the macarons to an airtight container.
4. Place the macarons in the fridge to age overnight. Bring to room temperature and enjoy.