Split vanilla bean open lengthwise and place in a heavy saucepan. Add half-and-half. Bring to a boil and cook over medium-low heat for about 10 minutes. Remove vanilla bean. In a bowl, beat egg yolks and sugar until smooth and creamy. Add a little hot half-and-half, whisking. Pour this mixture back into saucepan. Bring to a boil, whisking constantly until thick and creamy. Do not boil or custard will curdle. Remove custard sauce from heat. Beat until cool. Whip cream until soft peaks form, then add to custard.