Add half the icing sugar, activated charcoal and almond flour into a food processor and process until well combined. Repeat with the other half. This will help get rid of any lumps in the sugar. Alternatively, you may sift the two together. This must be done at least 3 times.
Empty the almond mixture into a large mixing bowl, add the first portion of egg whites and mix until it forms a paste. Cover with plastic wrap and set aside.
Add the sugar and water into a small saucepan. Give it a very gentle stir to get them mixed together. Bring to a boil on medium high heat, then turn down to a simmer. Add a candy thermometer to the pot to help you measure the temp of the syrup. As the syrup bubbles away it will splatter small bubbles of sugared water on the sides of the pot. Use a pastry brush dabbed in a little water to brush those back into the syrup. This will help prevent the syrup from crystallising. When the syrup reaches 115C, add the second portion of egg whites to the bowl of a stand mixer and start whisking them on medium/high speed to help break them apart and get them a little frothy.
When the syrup reaches 118C, pour it over the egg whites in a slow and steady stream.
Whisk to stiff peaks for about 6 min. Add the vanilla extract at about the 3 min point, whisk into the meringue for a couple of minutes. Stop the mixer and scrape down, then whisk for an extra couple of minutes. When you can turn the bowl over and the meringue doesn’t fall out, you know you’ve reached stiff peaks.
Grab a spatula full of the meringue and fold it into the almond-sugar mixture, mix until well combined. This allows the mixture to thin out a little before you add the rest of the mixture.
Fold everything together by going around the bowl with a spatula then through the middle (as demonstrated in the video). Continue folding until the batter gets thin enough that it drips off the spatula and falls in a ribbon. It should take about 10 seconds for the ribbon to disappear into the rest of the batter. That’s when you know the batter is ready to pipe.
Spoon the batter into a piping bag with a round tip.
Pipe rounds of batter about 5cm in diameter, spacing them 2cm apart on (flat) baking trays lined with baking parchment. Sprinkle with sprinkles.
Gently tap the tray on the work surface covered with a kitchen cloth. Leave to stand for at least 30 minutes, until a skin forms on the shells. They shouldn’t be sticky when you touch them. It’s at this point that you can preheat a fan forced oven to 180C (360F)
Bake for 12 minutes. If you feel your oven is causing the macarons to brown on one side (usually the side closest to the fan) turn the tray around about half way through baking. Once they’re baked, let them cool completely.
To prepare frosting add activate charcoal to chocolate buttercream and mix until well combined.
Frost a large bulb of frosting on one macaron using a round tip. Stick blackberries to it and sandwich with another macaron.