Preheat the oven to 200 degrees F. Double up two baking sheets and line the top one with a silicone mat.
If your eggs are not at room temperature, let them sit in a bowl of warm water before separating them. Warm eggs whip up easier.
In a food processor, pulse together the confectioners' sugar and almond meal until it is powdery. This usually takes about four 10-second pulses.
Sift the almond meal and confectioners' sugar, set aside.
In the bowl of a stand mixer combine the egg whites, sugar and cream of tartar. Using the whisk attachment, beat the egg whites on high speed until they are stiff peaks. They should still be glossy and smooth.
Gently fold the almond meal mixture into the egg whites.
Once the whites and almond meal are combined, the batter will still be too stiff to pipe. You will know they are right when you lift the rubber spatula out of the mixture and it runs off like a lava flow.
At this stiff stage is when you want to add your food coloring. Use a thick paste or gel, so that you get an intense color without adding too much liquid.
Once you have reached the right consistency, you are ready to pipe.
Set up an 18-inch piping bag with a large round tip. Fill the bag about 1/3 full. Holding the bag straight up and down and about a 1/4 inch above the silicone mat, squeeze until there is a dime-size mound of batter. The batter should spread slightly and not form a stiff peak. If it is not spreading well, squeeze it out of the bag and mix it for another few seconds, then refill the bag and try again.
Once you have them piped out, lift the tray about 4 inches off the counter and slam it down. This is meant to take out the air bubbles and flatten the tops of your macarons. Repeat three or four times, until they are smooth.
Double up the baking tray or the bottom of your macarons will darken and get too hard. Bake at 200 degrees F for 15 minutes. Rotate the tray and turn up the oven to 350 degrees F, bake for 8 to 10 minutes. They are done when they have puffed and the sides are set firm, but not hard. Take them out of the oven and cool completely. They can be frozen for up to a month before filling them.
To make the ganache:
Heat the cream over low heat, just until simmering. Turn off the heat and add the chopped chocolate and butter. Swirl the pan to make sure the chocolate is submerged in the cream, allow to sit for 3 minutes and then gently stir to combine. Add the peppermint extract. Pour into a bowl, cover with plastic and refrigerate until set.
Use a piping bag to fill the cooled macarons with a thin layer of peppermint ganache. Pipe a small dot of the ganache on top to act as glue for the crushed peppermint candies to stick to.
Serve the macarons right away or you can refrigerate them for several days.