Total Calories: 651
In bowl of mixer, cream sugar and butter together until light and fluffy add grated rind. Add eggs one at a time, beating well after each addition. Sift flour and baking powder together fold into creamed mixture just until well blended. Do not beat or cake will be tough. Butter and flour an 8-inch cake pan. Pour in batter, pushing batter out from middle, leaving a slight indentation in center. (This makes cake bake evenly without peak in center.) Bake in a preheated 350° F oven for 25 minutes. Allow to cool for 10 minutes turn out onto cake rack.
For glaze: Mix reserved orange juice and confectioners' sugar together. Spoon this mixture over warm cake, a little at a time. Repeat until all glaze is used up. If filling is desired, cake can be split in two when cold and filled with the following:
*In small saucepan, mix all ingredients except Grand Marnier. Constantly whisk over low heat until mixture thickens and coats a metal spoon, about 5 minutes. Take care: don't let mixture boil or cook without stirring or the eggs might scramble. Remove from heat, whisking to cool. Stir in Grand Marnier. Split cake in half horizontally and fill with this orange filling. Spoon glaze over top.
Note: This cake does not need any adjustments for high altitude.