1 cup Chelsea Icing Sugar
¾ cup ground almonds
2 large egg whites
Pinch of cream of tartar
¼ cup Chelsea Caster Sugar
Gel colour (as desired)

Lime Custard
2 cups custard powder
zest of 2-3 limes
juice of 2 limes

Preheat oven to 190°C. Line a baking tray with baking paper.

Sift icing sugar and ground almonds together into a bowl. Repeat, pressing through any large lumps.
Beat egg whites until foamy, add cream of tartar. Beat until soft peaks form.
Add Chelsea Caster Sugar and colour (if desired) and whisk until stiff peaks form.
Sift almond and Chelsea Icing Sugar mixture over egg mixture and fold until smooth and shiny.
Pipe mixture on to a baking paper lined baking tray. Tap bottom of the tray onto bench top to release any air. Stand at room temperature until caps look dull and skin has formed. Before putting macarons into the oven reduce temperature to 165°C place in oven and bake for 10 minutes. Rotate the tray half way through cooking time. Remove from oven and cool for 2-3 minutes before transferring to a wire rack.
Spoon a small amount of lime custard onto a macaron, sandwich together with another macaron. Repeat for the remainder.

Lime Custard
Make 2 cups of custard as per recipe on Edmonds Custard Box but double the amount of custard powder used. Once custard is thickened, add the zest of 2-3 limes and the juice of 2 limes. Mix lime juice and zest into the custard and set aside to cool.