Chocolate French Macarons with Peanut Butter Filling

Since the first time I tried a French Macaroon at Bouchon Bakery I have been hooked. My first attempt was horrific so I didn't try again until I was in pastry class. With my instructor?s help I did it and now I can't stop. There are just so many different kinds that you can make. The key is to make sure you whip the egg whites to stiff peaks and to let the piped out cookies sit at room temperature for 20 minutes before putting them in the oven. Those were my mistakes.
Chocolate French Macaroons
1-1/4 cups confectioner?s sugar
1-1/2 cups (4 ounces) sliced almonds, finely ground, or almond flour
All purpose flour for dipping
3 large egg whites
Pinch of salt
¼ cup granulated sugar
¼ teaspoon pure vanilla extract
2 Tablespoons Dutch-process cocoa powder
Directions
Preheat oven to 300 degrees. Sift confectioner?s sugar and cocoa powder into a bowl. Whisk in ground almonds; set aside. Line two baking sheets with parchment paper or nonstick baking mats, and mark circles using a 1-1/2 inch cookie cutter dipped in flour.
In the bowl of an electric mixer fitted with the whisk attachment, beat egg whites on medium speed until foamy; add salt. Gradually add granulated sugar, a teaspoon at a time, until the whites reach medium-soft peaks. Transfer to a large bowl.
Sprinkle half of the sugar-almond mixture over the egg-white mixture. Using a large rubber spatula, fold until just incorporated. Add ¼ teaspoon vanilla and remaining sugar-along mixture, folding just until incorporated. Firmly tap the bottom of the bowl on a counter or work surface to eliminate any air pockets.
Transfer mixture to a large pastry bag fitted with a ½ inch plain tip. Pipe mixture into marked circles on prepared baking sheet.
Bake, rotating sheets halfway through, until macaroons feel slightly firm to the touch and can be gently lifted off the parchment (the bottoms will be dry), 20 to 25 minutes. Let cool on the baking sheets for 5 minutes, then transfer parchment and macaroons to a wire rack to cool completely. Using a small offset spatula, carefully remove macaroons from parchment. Make filling, below.

Peanut Butter Filling
6 Tablespoons unsalted butter, room temperature
¾ cup confectioner?s sugar
¾ cup smooth peanut butter
3 Tablespoons heavy cream

In the bowl of an electric mixer fitted with the paddle attachment, combine all ingredients. Beat on medium-high speed until light and fluffy, about 5 minutes, scraping down the sides of the bowl as needed. Immediately, spread 2 teaspoons filling on the flat sides of half the macaroons; sandwich with the other halves, keeping flat sides down. Refrigerate until firm, about 20 minutes, before serving. Filled cookies can be kept in an airtight container in the refrigerator for up to 2 days.