Line 2 baking trays with baking paper. Process the almond meal and icing sugar in a food processor until combined, then sift twice. Place the eggwhite in the bowl of an electric mixer and beat on medium speed until frothy, then increase the speed while gradually adding the caster sugar. Continue beating until stiff peaks form. Mix in enough colouring for desired effect. Fold one-third into the almond mixture and combine well. Gently fold through the remaining eggwhite mixture; it should be glossy and thick, not thin and runny.
Transfer to a piping bag fitted with a 5 mm (¼ inch) plain nozzle and pipe 3 cm (1¼ inch) circles about 3 cm (1¼ inches) apart onto the trays. Leave for 1–6 hours (depending on the humidity) or until a crust forms; the macarons should no longer be sticky.
To make the curd, place the egg yolks, sugar, pulp and lemon juice in a saucepan over medium–low heat and, using a wooden spoon, stir continuously for 8–9 minutes or until thick and the mixture coats the spoon. Remove from the heat and add the butter, 1 cube at a time, beating well after each addition. Cover with plastic wrap and refrigerate for 1 hour.
Preheat the oven to 140°C (275°F/Gas 1). Bake the macarons for 15–18 minutes until they rise slightly. Immediately slide the macarons and paper off the trays onto wire racks to cool completely.
Transfer the curd to a piping bag fitted with a 1 cm (½ inch) plain nozzle and pipe about 1 teaspoon onto half of the macarons. Sandwich with the remaining macarons.
MAKES ABOUT 30
120 g (4¼ oz) almond meal (ground almonds)
220 g (7¾ oz) icing (confectioners’) sugar
110 g (3¾ oz) eggwhite
30 g (1 oz) caster (superfine) sugar
yellow food colouring, paste or powdered is preferable
PASSIONFRUIT CURD
5 egg yolks
165 g (5¾ oz/¾ cup) caster (superfine) sugar
125 ml (4½ fl oz/½ cup) passionfruit pulp
1 tablespoon lemon juice
80 g (2¾ oz) unsalted butter, cubed