Makes about 50 sandwiched macarons.
260 g almond flour (a little less than 2 3/4 cups)
230 g icing sugar (a little more than 1 3/4 cups)
200 g egg whites, aged* (approximately 6 extra-large eggs)
200 g granulated sugar (approximately 1 cup)
2 g cream of tartar (a little less than 1/2 tsp.)
gel food colouring
*Note: Age egg whites by placing egg whites in a bowl and covering with plastic wrap. Pierce small holes in the wrap and place in the fridge for one week. Allow the egg whites to come to room temperature before using.
Preheat oven to 325 degrees F.
Add almond flour and icing sugar in a bowl and mix. Batch by batch, grind the almond mixture in a food processor for a fine texture. Sift the ground almond mixture in a drum sieve over a bowl. Set aside.
Add egg whites to a mixing bowl and, using a mixer with whisk attachment, whip the egg whites until white and frothy. Add sugar and cream of tartar in three additions, mixing each addition until incorporated, and whip to stiff peaks.
Remove the bowl from the mixer and place on a work surface. Add the almond mixture to the egg white-sugar mixture in three additions by folding each addition with a spatula until incorporated. Add the food colouring at this time, if desired. Once all almond flour is added, continue to fold the batter until it reaches a desired piping consistency. The batter show flow like magma when folded.
Spatula the batter into a piping bag with piping tip. Pipe the batter in a 1-inch circle on a baking sheet lined with parchment paper. It is helpful to have a template with 1-inch circles drawn on it.
Tap down the baking sheet either by hitting the baking sheet against the work table or by hitting your hand under the baking sheet. This will deflate the meringue and flatten out your batter to release air bubbles.
Allow the batter to dry at room temperature for 20-40 minutes or until a skin has formed around the batter. This can be tested by gently touching the batter with your finger.
Once the batter is dry, bake for 10-13 minutes at 325 degrees F. The baking conditions are different for every oven. It may take some trial and error to get the right conditions.
Once baked, remove from oven and allow the macarons to come to room temperature before removing them from the baking sheet. The macarons are ready to be filled.