1-Preparing the Ingredients: Preheat your oven to 350°F (177°C). Grease and line three 8-inch cake pans with parchment paper, greasing the paper as well. If you prefer, you can use one 8-inch or 9-inch round pan or a 9×13-inch pan, adjusting baking time accordingly.

Lightly toast the pistachios for about 12 minutes to enhance their flavor, then let them cool completely. Pulse the pistachios in a food processor until finely ground, resembling soft crumbs but not pistachio butter. Set aside some for garnish.

2-Mixing the Batter: In a large bowl, whisk together the pistachio crumbs (about 1 and 1/2 cups), cake flour, baking powder, baking soda, and salt. Using an electric mixer, beat the butter and sugar on high speed until smooth and creamy, about 3 minutes. Add the egg whites (or whole egg) and beat until combined, approximately 2 minutes. Mix in the sour cream (or yogurt), vanilla extract, and almond extract if using.

Gradually add the dry ingredients to the wet mixture on low speed. Slowly pour in the milk and optional green food coloring while mixing until just combined. The batter will be thick and pale green.

3-Baking and Cooling: Divide the batter evenly among the prepared pans or pour into a single pan. Bake for 21-23 minutes if using 8-inch pans, or about 40 minutes if using a single 8-inch pan. Adjust as needed for different pan sizes. A toothpick inserted in the center should come out clean or with a few crumbs.

Allow the cakes to cool completely in the pans on wire racks before leveling and assembling.

4-Frosting and Assembly: For the cream cheese frosting, beat the softened cream cheese and butter together until smooth. Add confectioners’ sugar, vanilla, and salt. Beat at low speed to combine, then at high speed until creamy and spreadable. Adjust the consistency by adding more sugar to thicken or a little milk to thin. Refrigerate if the frosting becomes too soft.

Level the cooled cakes by trimming tops if needed. Layer the cakes with frosting between each layer and cover the top and sides with the remaining frosting. Garnish with crushed pistachios, fresh berries, or edible flowers. Refrigerate for at least 30 minutes before slicing for best results.