For the Shells

Cup of Yum
1. Line two large sheet pans with parchment paper or Silpat mats.
2. Add the egg whites and granulated sugar to a small heatproof bowl. Set the bowl over a small saucepan of simmering water.
3. Whisk the egg whites until the sugar has fully dissolved, about 2 minutes.
4. Next, transfer the egg whites to the bowl of a stand mixer fitted with the whisk attachment. Beat on medium-high speed until the egg whites form stiff peaks, about 3-4 minutes.
5. Use a fine-mesh sieve to sift the almond flour and powdered sugar into the egg whites. Fold the dry ingredients gently into the egg whites by making a "J" shape with your spatula.
6. Continue folding until the dry ingredients are fully incorporated. Make sure to scrape all the way to the bottom of the bowl.
7. Once all of the dry ingredients have been incorporated, smush the batter against the sides of the bowl and fold it back together. Repeat the smush-and-fold process a few times, or until the batter flows smoothly. When the meringue is ready to pipe, you’ll be able to draw a figure 8 without the stream breaking. If the meringue breaks while you draw the figure 8, smush and fold a few more times before retesting.
8. When the meringue flows smoothly, transfer it to a piping bag fitted with a small round top (Wilton #10-12).
9. Pipe 1½-inch circles on the sheet pan, making sure to pipe them at least 2 inches apart. Hold the tray 6-8 inches off the counter and drop it straight down. Repeat 6-8 times, or until it looks like any large air bubbles have popped. Repeat with the second tray.
10. Set the trays aside to rest until the macarons have developed a skin, about 30 minutes.
11. While the macarons rest, preheat your oven to 325°F.
12. The macarons are ready to bake when you can touch them gently without the meringue sticking to your finger.
13. Bake the macarons, one tray at time, for 14 minutes, turning the tray halfway through baking.
14. Allow the macarons to cool fully on the tray so they don’t stick.

For the Filling

1. Add the chopped chocolate to a small bowl and microwave it until melted. Set it aside to cool for a few minutes.
2. Add the softened butter to the bowl of a stand mixer fitted with the paddle attachment. Beat it on medium-high speed until light and fluffy.
3. With the mixer on low, slowly add the powdered sugar, followed by the vanilla extract. Turn the mixer to high speed and whip the filling until it’s light and fluffy, about 2 minutes.
4. Fold in the cooled, melted chocolate and transfer the filling to a piping bag fitted with your choice of tip.

Age and Assemble

1. Place the macaron shells in similar-sized pairs. Pipe a small dollop of filling onto the center of one macaron. Press another macaron on top and push them together gently, just until the filling reaches the edges. Repeat with the remaining macarons.
2. Transfer the filled macarons to an airtight container and store them in the fridge to age overnight.
3. Bring the macarons to room temperature and enjoy.