Line 2 large baking sheets with silicone baking sheets or parchment paper. Draw 1½ inch circles over the paper, 1 inch apart.
Combine almond meal and powdered sugar in a food processor and pulse a few times until well blended.
Sift through a fine mesh sieve. If there are more that 2 tbsp of the mixture in the sieve, process again and sift it again. Set aside.
In the bowl of a stand mixer, fitted with paddle attachment beat egg whites, cream of tartar and sugar on high speed for about 5 minutes, until stiff peaks form.
Add the almond meal and sugar mixture to the egg whites and start folding it, using a rubber spatula. Fold scraping the sides of the bowl and trying to deflate the meringue and incorporating the dry ingredients into it at the same time. Continue folding, until the batter is thick and glossy and reaches lava state consistency. When you pick some batter up with the spatula and drop it into the bowl, it has to settle into the rest within 20 seconds.
Fill a piping bag, fitted with 1/2 inch round tip with the batter.
Pipe shells onto the circles.
Tap each baking sheet on the counter 5-6 times, this will let any air bubbles out of the cookies. Sprinkle with coffee granules or cocoa powder.
Let cookie shells dry at room temperature for 40 minutes, before you bake them.
Preheat oven to 325 F. Bake cookie shells for 10-12 minutes, until set but not browned. If they are beginning to brown very quickly, you might need to turn the oven temperature down.
Transfer baking sheets to a wire rack and let cookies cool down completely.
Peel cookies off the parchment paper (silicone mats) and turn upside down. Be careful not to break them.