In a large bowl, sift and whisk together the flour, pistachio flour, salt, baking powder and baking soda.
In the bowl of a stand mixer fitted with the whisk attachment, mix the olive oil, lemon zest, milk, sour cream, eggs, egg white and vanilla extract on medium speed until thoroughly combined, about 30 seconds. Add the sugar and beat until well combined, another 30 seconds. With the mixer on low speed, add the dry ingredients a little at a time until the batter is fully integrated and smooth, 1 to 2 minutes. Do not overmix; the batter should be thoroughly mixed but loose. Pour the batter into the prepared cake pan and use a spatula to spread evenly.
