Make cake: Preheat oven to 350°F. Coat a 9-inch round cake pan (at least 2 inches deep) with olive-oil cooking spray. Line bottom with parchment; mist with spray.
In a bowl, whisk flour, baking powder and salt. In a separate bowl, combine sugar, zest and eggs. Using an electric mixer on high speed, beat mixture until pale and thickened, about 5 minutes. Reduce speed to low and beat in orange juice. Gradually add olive oil, beating constantly. Stop mixer and use a rubber spatula to fold in dry ingredients. Pour batter into prepared pan and bake until a toothpick inserted into center comes out clean, 35 to 40 minutes. Let cool in pan on a wire rack for 15 minutes. Run a small knife around edge of cake, then turn onto rack to let cool completely.
Make glaze: Whisk confectioners' sugar, milk and vanilla in a small bowl until smooth. Set cake and rack over a foil-lined rimmed baking sheet. Spread glaze on cooled cake, allowing it to drip over edges. Let glaze set for at least 20 minutes before serving.
lovely flavor, easy to make. almost like a sponge cake.
