Pistachio Macarons

Preheat oven to 350 degrees F. Line two baking sheets with parchment paper.

Sift the powdered sugar and the ground almonds together into a medium bowl. In the bowl of an electric mixture fitted with a whisk attachment, beat egg whites until foamy over medium speed. Add cream of tartar and continue to beat on high until soft peaks form. Add sugar and food coloring (if using) and beat to stiff peaks. Gently fold dry ingredients into egg whites until mixture is just smooth.

Fill a pastry bag fitted with a plain 1/2 inch tip with meringue mixture. Pipe 1 inch rounds onto baking trays approximately 2 inches apart. Tap trays on counter to remove air bubbles.

Sprinkle each macaron with chopped pistachios. Let trays stand about 20-30 minutes until a skin forms on the macarons.

Bake each tray about 15 minutes, until tops are firm and surface is dry. Let macarons cool completely and carefully remove from parchment.

Make filling: Place chocolate and cream in microwave safe bowl and microwave on high for 1 minute until chocolate melts. Stir to combine and mix in pistachio paste. Refrigerate for 10 minutes if mixture is thin.

Spread 1/2 teaspoon filling on the flat side of half of the macarons.

Sandwich with remaining macarons and refrigerate until firm, about 1 hour.