How to Make It
Preheat oven to 350°F. Grease and flour a tube or Bundt pan.
Gently zest the oranges (about 2 tablespoons). Squeeze 1 orange—or more if you've got stingy oranges—to equal 1/2 cup juice.
Beat eggs and sugar in a stand mixer on medium-high speed until mixture is fluffy and thick, about 5 minutes. Slowly beat in oil. Sprinkle in orange zest. Leave mixer running.
Meanwhile, whisk together flour, baking powder, and salt. Reduce mixer speed to low; gradually add flour mixture to wet ingredients. Gently stir in vanilla and 1/2 cup orange juice until batter is smooth.
Pour batter into prepared cake pan; bake until a cake tester comes out clean, about 40 minutes.