Put the pieces of white chocolate in a bowl, and sit this bowl over a pan over simmering water until it melts. stirring gently with a spatula.

When it's melted, keep aside.

Place the egg white in another bowl and place it over the same simmering water. Whisk the egg white till it reached soft peaks. Keep aside to cool.

In a third bowl, whisk cream till soft peak and add vanilla extract.

Once the egg is cool, fold it into the whipped cream.

Put a big dollop of egg+cream onto the slightly cooled chocolate and mix, and then gently fold the chocolate mixture into the cream.

Melt the butter and chocolate over a pan of simmering water. Once melted, set aside

In another bowl, put yolks, sugar and 2 tbsp water n whisk till thick n pale. Set aside to cool

In a third bowl, whip double cream till soft peaks.

When the chocolate and eggs have cooled down, fold the chocolate into the eggs.

Finally fold the egg + chocolate mixture gently into the cream.

To assemble:

Place 2 tablespoons of dark chocolate mousse in little cups. Top with 2 tablespoons of white chocolate mousse. Chill for at least 3 hours or overnight.

You can serve with strawberries or chocolate curls.