Beat the cream cheese, orange rind, olive oil, vanilla extract at medium speed of a mixer until well-blended. Add sugar and milk and beat at low speed until well-blended, pour over cooled cake and serve.
For the Cake
Preheat the oven to 325° and butter and flour a 10-cup bundt pan. In a bowl, using a handheld electric mixer, beat the eggs with the sugar, vanilla extract, and orange zest at medium-high speed until smooth. Gradually beat in the orange olive oil until creamy, for about 2 minutes. In a small bowl, whisk the cake flour with the baking powder and salt. Add the dry ingredients to the egg mixture in 3 batches, beating on medium speed between additions.
Scrape the batter into the prepared pan and bake in the center of the oven for about 1 hour, until a toothpick inserted in the center of the cake comes out clean. Let cool in the pan for 15 minutes, then invert onto a rack. Let the cake cool completely before glazing, cutting into slices, and serving.