• Line a cookie sheet with parchment or silpat mat and place a template beneath.
• In a food processor, pulse the almond flour, confectioner's sugar and blueberry powder together (about 10 pulses), or until well combined.
• Using the whisk attachment, whip the egg whites in a grease-free bowl of a stand mixer until foamy.
• Slowly add the granulated sugar to the egg whites, a little at a time and continue to whip on high until stiff peaks form. Do not over-whip.
• Remove bowl from mixer and sift the almond mixture onto the egg whites  in three additions. Use a clean, grease-free spatula to fold the the mixture into the egg whites. Should be the consistency of molasses when ready - at about 50 folds.
• Fit a piping bag with a 1.5" plain tip and fill the bag with the batter. Pipe small circles onto the parchment/baking mat. remove the template.
• Tap the pan on the counter firmly a few times to remove any air bubbles or peaks. Let the batter rest for 30 minutes to an hour to allow a skin to form on the tops of the piped macarons.
• While the batter rests, preheat the oven to 325ºF. Bake for 8 -10 minutes. Do not allow to brown. (bake time may differ for your oven)
• Remove from oven and allow to cool completely and pair up equal sized shells before assembling.

To make the ganache:

• Place chocolate in a heat-resistant bowl and melt over a double boiler. Set aside.
• Bring cream to a simmer in a pot over medium heat. Once the cream begins to bubble around the edges, remove from heat and immediately and add to the chocolate in three additions while stirring. 
• Add the mango puree and stir to incorporate fully. Add butter while mixture is still warm and whisk until completely melted and mixture appears smooth. If needed use a hand blender to emulsify.
• Allow to set to a consistency that is good for piping. Pipe generous amounts onto one of the paired shells and then sandwich the piped ganache with the second shell. 
• Place in an airtight container and allow to chill overnight before enjoying. Perfect for afternoon tea with friends!