Preheat oven to 350 degrees. Line the bottom of a 10-inch cake pan with parchment paper. Butter the paper and side of the pan and dust with flour.
In a large bowl using a mixer, beat the eggs with the sugar, orange zest and salt.
In a medium bowl combine the orange juice and olive oil. At a low speed, gradually beat the orange juice mixture into the egg mixture. Gradually beat in the 2 cups of flour (maybe 3 additions) until a smooth batter forms.
Scrape the batter into the prepared pan and bake for 45-50 minutes until a toothpick test comes out clean. Let the cake cool completely in pan on a wire rack. Unmold and discard parchment. Dust with confectioners’ sugar and serve.