White Chocolate Mousse

Ingredients
4 large egg yolks
1/3 cup sugar
3 tbsp cornstarch
1 1/2 cups milk
2 tsp vanilla
3 tbsp unsalted butter, softened
9 ounces fine-quality white chocolate, chopped
1 cup heavy cream


Directions

1. In a bowl, whisk together well the yolks, the sugar, and a pinch of salt.
2. Add the cornstarch, sifted, and whisk the mixture until it is just combined.
3. Add the milk, scalded, in a stream, whisking, transfer the mixture to a heavy saucepan, and boil it, whisking, for 1 minute, or until it is very thick and smooth.
4. Strain the pastry cream through a fine sieve into a bowl, stir in vanilla and the butter, and chill the pastry cream, its surface covered with plastic wrap, until it is cooled completely.
5. In a metal bowl set over barely simmering water melt the white chocolate, stirring occasionally, and let it cool to lukewarm.
6. In a large bowl whisk together the white chocolate and 1 cup of the pastry cream, reserving the remaining pastry cream for the raspberry mousse, until the mixture is combined well.
7. In a bowl with an electric mixer beat the heavy cream until it holds soft peaks, whisk 1/4 of it into the white chocolate mixture, and fold in the remaining whipped cream gently but thoroughly.