Preheat oven to 350ºF/180ºC. Grease well a 9-inch round pan.
In a large bowl Whisk together flour, baking powder, baking soda, and salt. Set aside.
In a medium bowl toss together sugar and lemon zest until combined. Add eggs and whisk well until combined. Whisk in olive oil and butter. Add lemon juice and buttermilk and whisk until combined. Add mixture to the flour mixture, and fold with a rubber spatula until combined and smooth. Once all is added, be careful not to overmix the batter.
Scrape batter into prepared pan and smooth the top. Bake for 40-45 minutes or until golden and a skewer inserted into the center of the cake comes out clean. Allow cake to cool completely on a wire rack. Dust cake lightly with powdered sugar before serving.
Store cake at room temperature in an airtight container for up to 2 days or refrigerate for up to 5 days. Serve at room temperature.