Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan.
In a large bowl, whisk together the flour, baking powder, baking soda, and salt.
In a separate bowl, whisk together the sugar and eggs until light and slightly fluffy.
Gradually add the olive oil to the egg mixture, whisking continuously until well combined. Then, add the buttermilk and vanilla extract, and whisk until smooth.
Slowly add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.
Pour the batter into the prepared cake pan and spread evenly. Sprinkle the top generously with sea salt.
Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.
Let the cake cool in the pan for 10 minutes before inverting it onto a wire rack to cool completely.