Preheat oven to 180C/160C fan-forced. Grease a 7cm-deep, 11cm x 21cm (base) loaf pan.
Using an electric mixer, beat butter, sugar and 2 teaspoons orange rind until light and fluffy. Add eggs, 1 at a time, beating after each addition. Stir in flour, orange juice and ½ cup creme fraiche.
Spoon mixture into prepared pan. Smooth surface. Bake for 1 hour to 1 hour 10 minutes or until a skewer inserted in centre of loaf comes out clean (cover loosely with foil if over-browning during cooking). Stand in pan for 10 minutes. Turn out onto a wire rack to cool completely.
Using an electric mixer, beat cream, icing sugar and remaining orange rind in a small bowl until just-firm peaks form. Add remaining creme fraiche. Fold until just combined. Spread frosting over top of loaf. Top with zest. Serve.
