Preheat your oven to 350°F.
Grease a 9-inch round cake pan, and line the bottom with parchment paper.
In a bowl, mix together the baking powder, salt, and flour, ensuring they are well combined.
In another bowl, beat the sugar and eggs until fluffy.
Add the orange zest and orange olive oil, continuing to mix until combined.
Gradually add the flour mixture and milk, alternating between the two.
Beat until the batter is smooth.
Pour the batter into the prepared cake pan and smooth the top.
Bake for about 30-35 minutes until golden and a toothpick comes out clean when inserted.