Grease 10-cup classic or fancy bundt or tube pan; dust with flour. Set aside.
In large bowl, beat butter with sugar until fluffy; beat in eggs, 1 at a time, beating well after each. Beat in orange rind and vanilla.
In separate bowl, whisk together flour, baking powder, baking soda and salt. Stir into butter mixture alternatively with sour cream, making 3 additions of dry ingredients and 2 of sour cream. Fold in carrots. Scrape into prepared pan; tap pan on counter and smooth top.
Bake in centre of 325F oven until cake tester inserted in centre comes out clean, about 1 hour. Let cool in pan on rack for 10 minutes. Remove from pan to rack; let cool completely.
Glaze: in small bowl, mix icing sugar with orange juice until smooth; brush over cake.
Garnish with chocolate curls and candied orange rind.