1: Preheat the oven to gas 2, 150°C, fan 130°C. Line 2 baking trays with nonstick baking paper. Whizz the almonds and icing sugar in a food processor until fine. Set aside.
2: Whisk the egg whites to soft peaks, then gradually whisk in the sugar, until glossy.
3: Sift the almond mixture over the egg whites and fold in with a large metal spoon. Spoon half the mixture into a second bowl. Taking care not to knock out any air, stir a drop of pink colouring into one bowl and a drop of yellow into the other. Spoon each mixture into a piping bag fitted with a 1cm nozzle. Pipe 2·5cm rounds onto the lined trays. Make 24 macaron halves of each colour.
4: Tap the baking trays to release any air bubbles. Set aside for 30 mins, or until the rounds are no longer sticky when touched. Bake in the oven for 10-12 mins, then set aside to cool completely.
5: Meanwhile, make the filling. Whisk the butter, icing sugar and almond extract, until light and fluffy. With a spoon, spread a thin layer of jam onto each yellow half. Then, using a small palette knife or a piping bag, top with a thin layer of buttercream. Sandwich with the pink macarons. Chill until ready to serve.