Preheat the oven to 155'C.
Pass the almonds and icing sugar through a medium sieve to remove any lumps.
Whisk the egg whites with 150g of caster sugar. Whisk until you have a semi-stiff and glossy meringue.
Stir in one third of the dry ingredients. Once incorporated, repeat with the second third and then the final third. Add the food colouring and work the mixture with a spatula until it is smooth, shiny and a dropping consistency.
Fill a piping bag with the macaroon mix and pipe the macaroons onto a lined baking tray. Tap the tray on your work surface to smooth out the tops and remove any large air bubbles. Leave the macaroons to dry for 15 minutes at room temperature. They are ready to cook when the surface is touch-dry. Transfer to the oven and bake for 10-12 minutes. The macaroons are cooked when the top is firm. Remove from the oven and leave to cool for 10 minutes. After 10 minutes, lift the macaroons from the baking parchment and turn them over. Allow to cool thoroughly before filling.
Finely dice the prunes.
Peel, core and finely dice the apple.
Mix together the egg yolks, half of the caster sugar and the cornflour.
Place the milk and the prunes in a saucepan and bring to the boil. Once boiling, add the milk to the egg yolk mixture a little at a time. Return the mixture to the pan and whisk over a medium to high heat for 3-4 minutes, gently bringing it back to the boil. Pour the mixture into a bowl, allow to cool and then refrigerate until set.
Place the remaining caster sugar in a pan and melt, without stirring, to form a caramel. Add the apple to the pan and cook for 2 minutes. Add the Calvados to pan then remove from the heat and allow to cool.
Fold the two cool mixture together and place in a piping bag.
Pipe the cream on to half of the macaroon shells. Top with a second macaroon shell to finish.
«The temperature of 150'C is based on using a fan assisted oven. If you do not have a fan assisted oven, preheat the oven to 160'C.»