Separate your eggs first, and place the whites in the bowl of a stand mixer and allow the whites to come to room temperature prior to whipping.
Make a template to make piping your macarons the same size much easier. I drew about (20) 1 1/2" circles on a piece of paper, and traced it onto (2) large sheets of parchment paper. Place the parchment paper face down on your baking sheets to prevent pen or pencil from transferring to your macarons!
Place the hazelnut meal, cocoa powder, powdered sugar, espresso powder, and salt in the bowl of a food processor and pulse until combined. Sift into a medium bowl. If there is a sizable amount of large bits of hazelnut, process in the food processor until finely ground, and sift into the bowl.
When the egg whites are room temperature, add the cream of tartar. Beat on medium speed with the whisk attachment until frothy. Gradually add the granulated sugar while continuing to mix, then increase the speed to medium high and beat until stiff, glossy peaks form. Your whites are done when you dip the wire whip into the whites, turn right side up, and the whites stand straight up.
Add half of the dry ingredients and fold with a rubber scraper from the middle down, then up and over, turning the bowl clockwise with each fold. Repeat with the other half of the dry ingredients, being careful not to over-fold and deflate the whites.
Place the batter in a large piping bag fitted with a large round tip (I used Wilton #806), and pipe onto the circles on your prepared baking sheets. Rap each baking sheet against the counter once to remove any air bubbles, and allow to sit at room temperature for 30-45 minutes to dry out.
Position your oven racks to the top and lower thirds of your oven. Preheat the oven to 325 degrees.
Bake the macarons for 15-16 minutes, rotating the pans from front to back and top to bottom halfway through baking time. The macarons are done when they just begin to separate from the parchment. Cool completely on a wire rack. Fill with the ganache, and place in an air tight container in the refrigerator overnight to allow the macarons to absorb some of the filling and soften slightly.