Shamrock Parfaits (Chocolate and Mint Mousse)

Heat 3/4 cup cream in a saucepan until hot. Whisk together yolks, sugar, and a pinch of salt in a bowl until combined well, then add hot cream in a slow stream, whisking until combined. Transfer mixture to saucepan and cook over moderately low heat, whisking constantly, just until it thickens. Add in the vanilla and chocolate chips and whisk until the chocolate is melted and fully incorporated. Set aside to cool.

Beat remaining 3 1/4 cups cream, 1/3 c. sugar ,peppermint oil and a few drops green food color in a bowl with an electric mixer until it just holds stiff peaks. Divide Whipped cream in half and set other half aside. Whisk one fourth of cream(of the half that was set aside) into chocolate custard to lighten, then fold in remaining cream gently but thoroughly. Spoon into a piping bag and set aside.

Pipe chocolate mousse and mint cream in alternating layers into 8-10 parfait dishes. Top with half a chocolate mint cookie and a sprig of mint. Let set in the refrigerator for 2-3 hours. Serve well chilled.