Blend together the icing sugar and almonds for a short while to combine.
In a large bowl, sift the icing sugar and almond mixture, discarding any large lumps that are left.
In a stand mixer, add your egg whites. Make sure the bowl and whisk you are using are spotlessly clean first!
Whisk the egg whites up to stiff peaks, and start adding the caster sugar teaspoon by teaspoon till all is incorporated. Whisk for another minute or so afterwards.
Once fully incorporated, continue to whisk for 1-2 minutes, and start adding your food colouring! I used a mix of ‘golden yellow’ and ‘amber leaf’ colours to get the colour I did - as it was all I had at the time!
Add in the sifted ground almonds and icing sugar mixture and fold through in as little folds as possible.
The next step is called 'Macaronage' where you basically press and wipe the mixture around the edges of the bowl to sort of de-fluff it in a way. It smooths the mixture out, making it better.
With a disposable piping bag, add a small round tip, add the mixtures. Carefully pipe the mixtures onto 2-3 large lined trays. The mixture does spread naturally, so don't pipe them that large otherwise they might end up touching.
Using a piping bag and a round nozzle, pipe the macarons either onto a baking tray lined with parchment paper. The mixture is quite runny, so be careful that it doesn’t go everywhere or you risk make the shells too big!
Once piped, tap the trays onto the work surface 5-6 times to get any air bubbles out, and leave on the side for 1 hour to form a skin.
Towards the end of the hour, turn your oven on to 130ºfan.
Bake the macarons for 16-20 minutes until they have risen to have their “feet”, and are starting to peel away from the tray – leave them to cool fully before trying to remove them.
Buttercream
In a bowl, cream the unsalted butter and icing sugar together until smooth and supple, and add the salted caramel sauce and beat again.
Decoration & Filling
Once the shells have cooled – remove carefully from your trays and line them up.
Melt your dark chocolate (I do mine in the microwave in short bursts), and drizzle it on to of your shells.
Add some sprinkles of your choice, and leave to dry.
Transfer the mixture to a piping bag with a piping nozzle of your choice fitted. Pipe some of the buttercream in a circle onto half of the macaron shells.
Fill the middle of the buttercream circle with some salted caramel sauce.
Sandwich together with the remaining shells.
Notes
I would recommend using parchment paper as opposed to a macaron mat (I find that sometimes they can stick) - but you can buy some with macaron shapes drawn on them already, or you can draw the circles yourself - or go freehand like me!
The Macarons last for up to 7 days in an airtight container in the refrigerator, or you can freeze the shells for up to 3 months.