Preheat the oven to 350F.
Spray a bundt pan with baking spray. Alternatively, you can grease and flour the pan if you do not have baking spray.
In medium bowl, whisk together the flour, baking powder, salt and pistachios. Set aside.
In another medium bowl, combine the granulated sugar and orange zest. Work the zest into the sugar with your fingers until the sugar is clumpy, pale orange and super fragrant. Set aside.
In the bowl of a stand mixer fitted with a whisk attachment, beat the eggs on high speed for 3 minutes.
Reduce the speed to medium high and add the orange sugar and continue to beat until the mixture is a pale yellow color and has thickened.
Reduce the speed to medium and stream in the olive oil.
Add the milk and vanilla extract, mixing until just combined.
Remove the bowl from the stand mixer. Fold in the flour mixture into the egg mixture in 3 parts.
Pour the mixture into the prepared bundt pan and smooth the top with an offset spatula.
Bake for 45-40 minutes until golden brown, and a toothpick, when inserted into the center of the cake comes out with few crumbs and no wet batter. Do not overbake.
Leave the cake in the pan to cool 10-15 minutes before turning out onto a cooling rack to cool completely.