Add the pistachios to a food processor and process them on high speed until finely ground. Set a heaping half cup of the ground pistachios to the side.
Add the remaining pistachios to a large bowl and whisk together with the flour, cornstarch, baking soda, baking powder, and salt. Set aside.
Next, add the butter to a stand mixer with the paddle attachment and whip on high speed for 5 to 7 minutes or until light and fluffy.
Add in the sugar on low speed so that it does not go everywhere, and then continue to mix on high speed for 3 to 4 minutes.
Next, turn the speed down to low-medium and add the vanilla. Then, add the eggs and egg whites a few at a time. Don’t mix in the next batch until the first batch of eggs is completely mixed in. Stop and scrape the bowl. On low speed, slowly add in the oil and mix until incorporated.
On low speed, add in a third of the dry ingredients (flour mixture). Once it’s fully mixed, pour in half of the 2 1/4 cups of whole milk. Once that’s in there, go back to the dry ingredients and add in a third. Stop and scrape the bowl. Then, add the remaining milk, and finally, the last of the dry ingredients. Give it a quick blast on high speed for 10 seconds to incorporate, and then remove the bowl from the mixer.
Now, evenly divide the batter between the three cake tins that have a parchment rounds in them and have been sprayed with non-stick spray.
Bake on a middle rack at 350°F for 30 to 32 minutes or until just firm in the center. I usually come back after half the cooking time and rotate the cakes to ensure they are cooking evenly.
Remove the cakes and place them on a rack to cool to room temperature, which takes about 90 minutes.
In the meantime, make the cream cheese frosting recipe x 2.
Once cooked, remove the cakes and, using a serrated knife, carefully cut off the rounded part of the cake on top so that it is flat.
Ice the cake in layers until it is completely coated, both between the layers and on the sides, and on top.
Garnish by sprinkling the remaining ground pistachios on top. Add on optional raspberries.
Notes
I made this cake in three 8-inch round cake tins. If you’re looking for a change, you can bake the cakes in one or two bundt pans (depending on the size), two 11×7-inch rectangular pans, or two 9×5-inch loaf pans instead.Toast the pistachios: Reveal the hidden oils and aromas in the pistachios by toasting them in a dry skillet over medium heat until they start to turn golden. Toasting pistachios won't keep their bright green color in the cake, but it will boost their nutty flavors to a whole new level.Don’t overmix the batter: Because this cake is very delicate, mix the dry and wet ingredients only until just combined, ensuring no dry flour remains in the bowl. Overmixing the batter will deflate the air bubbles and make the cake flat, dense, or gummy.For even baking, rotate the cake pans in the oven halfway through the baking time to help them cook evenly.Check that the cakes are done: You’ll know each cake layer is finished baking when the batter in the center is no longer jiggling and when a toothpick inserted into the middle comes out clean or with a few moist crumbs attached.More decoration ideas: Decorate the cake with whole or ground pistachios (in the middle and/or in a circle around the edges), dollops of piped icing, fresh fruit (like raspberries, cherries, apricots, or peaches), edible flowers, or a drizzle of honey.Make-Ahead: You can make the cake layers and icing up to 1 day ahead of time.How to Store: Cover the decorated cake and keep it on the kitchen counter for up to 5 days or in the refrigerator for up to 1 week. The undecorated and covered cake layers will also freeze well for up to 3 months. Thaw the cake in the fridge overnight before decorating and serving.