Prepare an 8-inch round cake pan by brushing the sides and bottom with olive oil, then dust it with flour, removing any excess. Then line the bottom of the pan with a round of parchment paper to help it release after baking.

In a medium bowl, combine all-purpose flour, almond flour, salt, baking powder, and baking soda, and give it a quick whisk.

In a bowl of a stand mixer, combine eggs, sugar, and orange zest. Turn on the mixer and beat the egg mixture double in size and look light and fluffy.

Add the orange juice and buttermilk and continue beating until the mixture is smooth.

With the mixer running on low, start slowly pouring the olive oil. Once it is fully incorporated, add the sifted dry ingredients and mix until no streaks of flour remain.

Pour the cake batter into the prepared pan and sprinkle the top with granulated sugar.