01 - Preheat oven to 350°F. Grease and flour a 9-inch round cake pan or line with parchment paper.
02 - Whisk together flour, baking powder, baking soda, and salt in a medium bowl until thoroughly mixed.
03 - In a large bowl, beat sugar, vegetable oil, and eggs until mixture is light and creamy.
04 - Add fresh orange juice, orange zest, milk, and vanilla extract to wet ingredients. Stir until evenly combined.
05 - Gradually fold the dry ingredients into the wet mixture until just combined, taking care not to overmix.
06 - Pour the batter into the prepared pan and smooth the surface evenly.
07 - Bake for 35 to 40 minutes or until a toothpick inserted in the center comes out clean.
08 - Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
09 - Whisk powdered sugar with orange juice until smooth and pourable; drizzle over the cooled cake before serving.