Sift the ground almonds and icing sugar into a bowl; set aside. In a separate bowl, whisk the egg whites until frothy. Add 1/3 of the sugar a little at a time, whisking until the egg whites are smooth and shiny. Gradually add the remaining sugar whisking until stiff peaks form. Add the food colouring and combine until evenly distributed. Fold in the dry ingredients, cutting straight down to the bottom of the bowl with a spatula, and lifting up the contents, bring the spatula up the side of the bowl while giving it a quarter turn. Continue to fold until the meringue loses volume and becomes smooth and shiny (Macaronner*). Fit a piping bag with a 8 mm round tip and fill with the macaron batter.
Cover a baking tray with baking parchment; pipe small rounds of batter, approximately 5 cm in diameter, in staggered lines on the tray so they won’t touch while baking. Lightly tap the baking tray on the work surface to remove any air bubbles; set aside at room temperature for 30 minutes.
Preheat the oven to 160 -170°C (320-338°F).
Bake the french macarons for approximately 18 minutes depending on the oven. Remove from the baking tray and cool on a rack.
In a saucepan, bring the 90 ml of cream and coconut milk to the boil. In a small bowl mix the tablespoon of cream with the potato starch, pour into the hot liquid. Whisk continually back to the boil. Pour onto the white chocolate, add the Malibu and stir in with a whisk.
Leave to cool, then add the butter pieces, and mix using a hand held blender. Refrigerate for 1 hour.
Fit a piping bag with a star tip, fill with the coconut filling; pipe balls of ganache onto the flat side of half the macarons; top with the remaining halves, pressing lightly to adhere. Ideally refrigerate overnight before serving.
* Macaronner: Essential step for obtaining smooth and shiny shells, the macaronnage consists of decreasing the volume of the egg white meringue. This technical gesture is done by hand and will enable air bubbles to escape from the preparation ensuring that the macarons are smooth and homogeneous once removed from the oven.
Recipe adapted and translated from the book “L’École de la Pâtisserie” by Le Cordon Bleu® institute and publisher Larousse.