Easter Chocolate Mousse

In a medium saucepan, heat 3/4 cup cream until hot. (Do not boil.) In a medium bowl, whisk together yolks, sugar, and a pinch of salt; add hot cream in a slow stream, whisking until combined. Transfer mixture to saucepan, and cook over medium-low heat, stirring constantly, until an instant-read thermometer reads 160 degrees. Pour custard through a fine-mesh sieve into a bowl, and stir in vanilla.

In a large bowl, beat remaining cream at medium-high speed with an electric mixer until stiff peaks form. Whisk one-fourth of whipped cream into chocolate custard to lighten; gently fold in remaining whipped cream. Spoon mousse into a pastry bag fitted with star tip. Pipe mouse into egg shells that are open on one end and cleaned thoroughly in hot soapy water.