Heat oven to 350°F. Spray three 8-inch cake pans with baking spray or butter and flour.
In a medium bowl, use a whisk to combine flour, baking powder, baking soda and salt; set aside.
Place 1/2 cup sugar and 1 cup pistachios into the bowl of a food processor fitted with metal blade; process until finely ground. Remove from the food processor and roughly chop the remaining 1/2 cup for garnishing the top.
Combine ground pistachio mixture, remaining 1 1/2 cups sugar and 1 cup butter in a large bowl, Beat with an electric mixer at medium speed, stopping to scrape the bowl occasionally, continuing until creamy..
Add the eggs one at a time, beating well after each addition. To the butter mixture add the lemon zest, vanilla extract and almond extract; mix well.
Lower the speed of the mixer and add the sifted dry ingredients alternately with the buttermilk to the wet ingredients, beating at low speed after each addition, just until mixed. Add 1-2 drops of green food coloring adjusting the amount to your taste, beating on low just until incorporated.
Divide the cake batter evenly between the prepared pans. Place into the oven and bake for 23-25 minutes or until a toothpick inserted into the center of the cake comes back clean.
Let layers cool in the pan for 10 minutes, then remove from pans to a wire rack and let cake cool completely.
Meanwhile, make the Cream Cheese Frosting adding lemon zest.
Assemble: Center one cake layer on a cake stand. Frost with cream cheese frosting and sprinkle with 1/4 cup chopped pistachios. Repeat with all three layers. (You should end with 1/2 cup chopped pistachios for the top.)
Frost the top and sides of the cake. Decorate the top as desired with lemon curls and lemon slices, then sprinkle with chopped pistachios.
Chill until serving.
Pro Tip Line the Cake Stand with Parchment Paper: When frosting this cake, cut strips of parchment paper or wax paper and line the edges of the cake stand. This prevents the frosting from getting all over the cake pedastal and keeps it clean for serving. Carefully pull the strips out from under the cake as soon as you're finished assembling and frosting.