This recipe makes about 18 - 24 Macaron halves depending on the size that you pipe them. Prepare the baking tray by cutting a sheet of baking paper to the size of the tray. Ensure that the egg whites to be used in the Macaron recipe have been aged for at least 2 hours and are at room temperature (this ensures maximum whipping volume).
Into a medium sized mixing bowl, sift the almond flour and icing sugar. If the almond flour is not finely ground, use a food processor to grind it down first, as it is essential that all the powders are fine in texture.
In a separate mixing bowl, beat the egg whites with the cream of tartar, slowly adding the castor sugar till the meringue mixture holds a stiff peak and doesn't droop. Add the gel food colouring just before this stage, you want to aim for a colour slightly darker than the final desired colour as the icing sugar and baking process will lighten the final colour. Note, do not over beat as the meringue mixture may break. Next sift the almond flour and icing sugar mixture (second sifting) into the meringue mixture in three parts. Each time fold by angling the spatula and scooping the sides of the bowl, taking the mixture up and over to the center, then pounding down gently into the center of the meringue. Repeat this process, counting the folding until the mixture resembles a molten lava texture, usually folding the mixture around 50 times total.
Work quickly now, scoop the mixture into a piping bag fitted with a 1 cm tip and pipe about 3 - 4 cm round circles onto the baking paper, leave a 1 - 2 cm space between each circle. A this point each Macaron half should slowly spread into a flat, circular round and loose their peaks after about 2 minutes after piping. If the mixture is too thick the Macarons will keep the peak and needs to be folded a little longer.
Once all the Macaron halves are piped out leave them to set for about 45 minutes to an hour before placing in the oven. Preheat the oven to 150 - 160 °C depending on the oven, if possible use an oven with a fan. Once you can lightly touch the tops of the Macarons without the mixture sticking to your fingers, they are ready to go into the oven. Place them in the oven for 14 - 18 minutes, halfway through cooking switch the position of the oven tray to allow even cooking (If only using one tray, remove an place it back in the oven, to allow excess humidity to escape). The Macarons are done when they lift slightly off the baking paper, it is important that they rise to form a short ruffled skirt/foot. Once they are done remove them from the oven and allow to cool completely before peeling off the baking paper. If you struggle to remove them from the baking paper, do not pull them off directly, rather fold the paper under, rolling it between your fingers till the Macaron slides off the paper.
Meanwhile, start with the Butter-cream filling. In a bowl, beat the butter until it is light and fluffy like mayonnaise. In a separate bowl beat the egg yolks and castor sugar till light and creamy. Add the milk to the egg mixture and place it on a very low heat (mark 3) on the stove, mix constantly with a spatula until the custard thickens. Remove the custard from the stove and beat till the mixture is cool, then mix the butter into the custard slowly in three parts, the butter should give the custard mixture 'body'. Once the mixture is smooth and creamy add the gel food colouring, Strawberry flavour and tartaric acid (dissolve in the flavouring).
Sandwich a thick layer of the Butter-cream filling between two Macaron halves. Note, although the Butter-cream filling is light and fluffy at the time of making, it sets in the fridge as normal butter would, so don't skimp on the filling. The Macarons are served best at room temperature, after maturing in the refrigerator for 1 - 2 days. Store in an airtight container, in the refrigerator for up to a week. Makes 10 - 12 Macarons, enough for a small dinner party of about four or five people.
