Preheat the oven to 350°F/177ºC. Prepare three 6-inch (15cm) or two 8-inch (20cm) cake pans by spraying the sides with cooking spray and fitting a parchment paper circle to the bottom of the pan.

Using a food processor, grind the pistachios into fine crumbs. You’ll still have about 1 and ½ cups of crumbs. Place 1 ¼ Cups (160g) of the pistachio crumbs into a medium bowl and set the rest of the crumbs aside in a smaller bowl to use as garnish on the decorated cake.

In the medium bowl with the pistachio crumbs, add the sifted cake flour, baking powder, baking soda, and salt. Whisk to combine and set aside.

In the bowl of your stand mixer fitted with the paddle attachment, beat the butter on high for two minutes until it’s light and creamy. Add the sugar and vegetable oil, then continue to mix on medium-high for another two minutes, scraping down the bowl and paddle as needed. Turn the mixer to low speed and add the egg whites one at a time, mixing until well combined. Add the sour cream, vanilla extract, and almond extract and mix for two minutes on high speed. Scrape down the bowl and paddle once more.

Turn the mixer to low and add in the dry ingredients all at once. When they’re just beginning to combine, add the green food coloring (if using) and the whole milk in a slow, steady stream. Continue to mix on low until incorporated, about 1 minute.

Pour the batter evenly into the prepared cake pans and bake for 28-32 minutes. They’re done when they spring back to the touch and a toothpick inserted into the middle comes out clean. Let the cakes cool in the pan for five minutes before turning them out onto a wire rack for an additional few hours of cooling.

With a food processor, grind the raspberries into a fine powder. Sift out the seeds and set the powder aside.

Whip the butter using a stand mixer with a paddle attachment on medium-high speed until it’s creamy and light in color (5 minutes). Add vanilla, milk, and raspberry powder and continue to mix on medium until fully combined.

Add the powdered sugar one cup at a time and mix on low speed, scraping down the bowl and paddle after each addition. Add a pinch of salt and mix on low speed until fully combined and smooth, 1-2 minutes.

Whip the butter using a stand mixer with a paddle attachment on medium-high speed until it’s creamy and almost white in color (7 minutes). Turn the mixer to low speed and add the powdered sugar a cup at a time, scraping down the bowl and paddle as needed. Add the vanilla extract and mix on low speed until fully combined.

Add the mascarpone and a pinch of salt. Mix on low speed until just incorporated, about 30 seconds. Give the buttercream a few stirs with your rubber spatula by hand to make sure it's all mixed in without over mixing.

Once the pistachio cakes are completely cooled, level them to your desired height. Add a swipe of raspberry buttercream onto a cardboard cake circle and place the first cake layer on top. Add a layer of raspberry buttercream as filling, then repeat the filling and stacking process with the final cake layer.

Crumb coat the cake with raspberry buttercream, then place it in the refrigerator for at least 30 minutes to let the buttercream set firm.

To create the design, frost the cake with mascarpone frosting and use a cake comb to create rounded texture on the sides. Keep the top edges raw. While the frosting is still tacky, gently press the reserved pistachio crumbs around the bottom third of the cake. Finish by garnishing the top of the cake with fresh raspberries and more pistachio crumbs.