FOR BUTTERCREAM: Whisk egg yolks, sugar and flour in medium bowl to blend well. Bring half and half to simmer in heavy medium saucepan. Slowly whisk hot half and half into egg mixture. Return egg mixture to same saucepan and cook until mixture boils and thickens, whisking constantly. Transfer mixture to medium bowl. Add chocolate and orange peel and stir until mixture is smooth. Press plastic wrap onto surface f pastry cream to prevent skin from orming. Cool completely. (Pastry cream can be prepared 1 day ahead. Refrigerate. Bring to room temperature before continuing.) �contined�