• In a food processor, combine the confectioners sugar, almond meal, and matcha. Pulse until all ingredients are finely combined. Set aside.
• In a standing mixer, fitted with the whisk attachment, begin to whisk the egg whites and add the granulated sugar right after you get the mixer started. Mix on medium speed until egg whites form firm peaks. (If you stop the mixer and lift the whisk it will form a peak and doesn't drip off the attachment they are ready.)
• Using a rubber spatula, delicately fold in the dry ingredients to combine without breaking the fluffy egg whites - exactly 40 turns with the spatula to get the perfect consistency with combined ingredients. Carefully transfer mixture to a piping bag with a round piping tip and pipe 1.5" circles onto baking sheets fitting with parchment paper.
• Once piped, hit the baking sheets on the counter top to release the air bubbles in the cookies.
• Preheat your oven to 300F and let the cookies rest for about 45 minutes to 1 hour. The cookies will be ready when they develop a 'skin' and you can touch the cookie and the batter does not stick to your finger. Bake one tray at a time, one the middle rack of your oven, for 20-25 minutes.

For the Dark Chocolate Ganache:

• Melt the dark chocolate chips in a heat proof bowl over a sauce pan with barely simmering water.
• Once chocolate has melted, remove from heat and let cool lightly - about 5 minutes. Carefully fold in sour cream until completely incorporated. Fit into a piping bag with a small round tip or just cut the tip off the bag if you use disposable plastic bags. Pipe the ganache onto the flat side of a macaroon and top with the flat side of another macaron.