Preheat your oven to 160°C with the door ever so slightly ajar to let out any moisture. Sometimes a wooden spoon wedged between the door can help.
Prepare a large baking tray with greaseproof paper or a silicon macaron mat.
Place a 1cm plain nozzle into a snipped pastry bag.
Crack two medium eggs and carefully separate the whites into a clean bowl or freestanding mixer fitted with the whisk attachment. Check to see you have 50g.
Add caster sugar to the egg whites and whisk until you have very stiff peaks.
Add almonds and icing sugar to the meringue then using a spatula (silicon is preferable), fold in the dry ingredients. Lift the spatula toward the centre of the mixture and press down on it, rotating the bowl as you go. You should have a ribbon of batter the consistency of treacle that takes about 20 seconds to be incorporated back into the mixture. If it's thicker than this you've under mixed and if it's thinner you have over mixed the batter and the shells will spread too much when piped.
Pour and scrape out the batter into the pastry bag. Twist the top and hold with one hand. With the other more dominant hand remove the peg at the bottom and hold for control.
Pipe generous rounds of approximately 3cm diameter.
To remove any air bubbles, tap the baking sheet against your counter several times.
Now the fun part! Lightly sieve over your macarons a sprinkling of dried beetroot powder.
Let the macarons rest for 30 mins until the tops form a skin.
Whilst the macarons are resting you can prepare the beetroot and chocolate ganache: blend the beetroot and the milk together until very fine. Then over a medium heat in a small pan until just below boiling. You should see bubbles along the rim. Turn off the heat and strain and press all of the juice over the chocolate. Whisk well until smooth and glossy.
Pour the ganache into another pastry bag placed in a tall glass. Twist at the top and leave to cool for at least two hours at room temperature to thicken.
Back to the macarons. Bake in the oven for 15 mins. If they are sticking to the baking sheet put them in for another five mins. Check at five minute intervals until they come away from the mat easily.
If they are still sticking after 30 minutes in the oven remove and gently prise away from the mat with a knife.
Spread across a wire rack. Let cool and completely harden for about 30 mins.
Now the filling. You can fill straight away or the shells can be prepared 1-2 days in advance, before filling, if kept in an airtight container. They can also be frozen and filled at a later date.
Snip off 1 cm off the end of the pastry bag filled with ganache and fill half the macaron shells. Match them up according to size to form sandwiches.
You can eat straight away of course but the macarons are at their best 24 hours later. Store them in an airtight container in the refrigerator and bring them to room temperature before you serve them. This process is called "aging" the macarons and allows the filling to soften the inside of the macaron shells a bit, lending more moistness. The outer shells will remain crisp. Yummy!