VANILLA MACARON SHELLS
In a mixing bowl with a paddle attachment, make an almond paste with the ground almonds, icing sugar, vanilla powder and the first quantity of egg whites. Make an Italian meringue with the sugar and water cooked to 118°C and poured over the second quantity of egg whites which are being slightly whisked. Allow the meringue to turn for a few minutes and then pour (still warm at 40°C) onto the almond paste little by little. Make sure not to make any grains in the mixture. Work by hand and 'macaroner' the mixture and pipe onto a "silpat" sheet or onto sheets of silicon paper spaced regularly. Bake the macarons in a fan forced oven at 150°C for 15 min. Allow to cool.

VANILLA GANACHE
In a saucepan, heat the cream, vanilla extract and vanilla powder. Pour the boiling mixture over the white chocolate and the cocoa butter.
Mix together then cover with film on contact with the ganache. Cool down the mixture in the refrigerator overnight.

ASSEMBLY AND FINISHING
Turn over half of the macarons, then using a piping bag fitted with a plain no°12 nozzle, fill generously with the vanilla ganache. Close the filled macarons with a macaron of a similar size.
Allow the macarons to mature overnight in the refrigerator before freezing or tasting.