Preheat the oven to 160'C.
Make the macaroon shells: place the ground almonds and the icing sugar in a food processor and mix to give a fine, lump-free powder.
Place the water and the caster sugar in a saucepan and heat to 118'C, stirring continuously. Whilst this mixture is heating, whisk 75g of egg whites. Once the sugar has reached 118'C, add it to the egg whites and whisk until the mixture cools down. Add the food colouring and mix gently.
Add the remaining egg whites to the icing sugar and almond mixture. Add a spoonful of the meringue mixture, mix together and then fold in the rest of the meringue. Once the mixture reaches the ribbon stage, place it in a piping bag and then pipe the macaroons on to a lined baking sheet. Gently tap the baking tray down on to the work surface. Transfer to the oven and cook for 10 minutes, turning the baking tray around after 5 minutes.
Grate the tonka bean.
Place the milk and grated tonka bean in a saucepan and bring to the boil.
Place the egg yolks, corn flour, espelette pepper and caster sugar in a bowl and mix together.
Once the milk has come to the boil, begin adding it to the egg yolk mixture a little at a time. Once all of the milk had been incorporated into the egg yolks, return the mixture to the pan and whisk over a medium to high heat for 3-4 minutes, gently bringing it to the boil. Once boiling, pour the liquid into a bowl and add the White chocolate while continuously whisking until you have a smooth mixture.
Chill in the fridge.
«It's a good idea, after piping, to leave the macaroons to rest for 10 minutes before cooking.»