Sift together the flour, baking powder and salt. Set aside.
Whip butter with sugar, vanilla and orange peel until mixture is soft. Add eggs gradually, beating well after each addition.
Lower speed and add flour mixture alternating with milk (start and end with the flour). Transfer mixture to a previously greased tube pan and bake in preheated moderate oven to 350ºF (180º C) for 40 minutes or until cake is done.
While cake is baking, place butter, sugar and orange juice in a saucepan and bring to a boil for 5 minutes. Once cake is done, remove it from the oven and pour topping over cake. Separate sides of cake from pan so the syrup goes in and moists the cake.
Cool completely and invert onto a serving dish.