Preheat the oven to 155'C.
Sift the ground almonds and the icing sugar together.
Whisk the egg whites until white and fluffy and then add the caster sugar to the the egg whites and continue whisking until you have stiff, glossy peaks.
Fold the ground almonds and icing sugar into the meringue mixture.
Cut and fold the mixture with a spatula until all of the dry ingredients are incorporated and the mixture is smooth, shiny and has reached the ribbon stage.
Carefully add the food colouring making sure not to overwork the mixture. Spoon the mixture into a piping bag.
Pipe 2cm circles in straight lines across a baking sheet lined with a silicon paper. Leave a 1 cm gap between each macaroon shell. Drop the tray of macaroons onto the work surface from about 30 cm to remove any large air bubbles.
Allow the macaroons to rest at room temperature for 20 minutes or until the macaroon shells are no longer sticky to touch.
Bake in the oven for 15 minutes. If you are baking lots of macaroons you may need to keep the oven door slightly ajar (with a spoon or paper) to prevent steam building up in the oven.After 15 minutes, check the macaroons are cooked by gently lifting a macaroon at the edge of a tray. If the test macaroon does not stick, allow the tray of macaroons to finish cooking on the tray as it cools.
Allow the macaroons to cool completely before filling.
Place the milk and the pistachio paste in a pan and bring to the boil.
Place the egg yolks, the caster sugar, corn flour in a bowl and mix.
Once the milk is boiling, add it little by little to the egg yolk mixture. Return the mixture to the pan and whisk over a medium to high heat for 3-4 minutes, gently bringing it to the boil. Transfer to a bowl, cover with cling film and chill in the fridge.
Whip the double cream until thick and then gently fold into the pistachio cream.
Fill half of the macaroon shells with the pistachio cream then add half a raspberry. Top with a second macaroon shell to finish.
«If preparing in advance, place the macaroons in the fridge until ready to serve - this will allow them to firm up.»