Basic Macaron Shell adapted from How To Cook That
165 cup icing sugar
To make Blackberry Macaron Shells
Preheat oven to 320F (160 degrees Celsius). Use a thermometer to be exactly precise. (I usually start to preheat the oven while I wait for macarons to dry)
Sift together the icing sugar and almond meal using a coarse sieve (if you use a fine sieve the almond meal will not go through). Discard any gritty bits of almond meal that do not go through.
Beat together the egg whites and caster sugar on high speed until they are stiff enough that you can turn the bowl upside down without them falling out. Beat for an additional 2 minutes. Add the almond icing sugar mixture and fold in using a rubber spatula.
Keep gently folding until the mixture looks like lava, it should have some movement but not be runny. While you are folding periodically scrape down the sides of the bowl and the spatula to make sure everything is mixed uniformly. Add in the red food coloring to half the mixture. Place the mixture in a piping bag. Place the other white half of the mixture in a separate piping bag. Cut the tips and place the 2 piping bags into one giant piping bag with a round nozzle.
Allow to dry until a shell has formed around the macarons, and then place in the oven. Bake at 160 deg C until a foot has formed and the shells are crisp. This took roughly 10 minutes. Try not to open the oven during the cooking process as this will cause a drop in oven temp and may make your macarons hollow.
Cool and then gently peel off the baking paper (if you can’t do this easily the shells are not done yet) and pair similar sized shells. Sometimes I like to flip the macarons over to prevent hollows as it cools (not sure how effective it actually is but no harm).
To make Peppermint Buttercream filling:
Start with 150 g butter and beat well with icing sugar (sifted). Add 1-2 tablespoons of whole milk. Mix for 3-4 minutes until light and fluffy. Add peppermint extract to taste.
Place buttercream between two cooled macaron shells. Roll the edges with crushed candy canes.