Step 1

Preheat your oven to 350°F (175°C) and grease and line with baking paper two 8-inch round pans. Then, wrap them with wet cake/towel-strips.

Step 2

Ground the pistachios: In a food processor, process one cup flour, one cup sugar and the pistachios until finely ground (processing nuts with the flour and sugar prevents them from turning pasty).

Step 3

Prepare the dry ingredients: In the bowl of your electric mixer combine all of the dry ingredients (flour, sugar, pistachios, salt, baking powder, and cardamom) and mix for 10-20 seconds until well combined. Add the butter and mix on low speed until the mixture resembles wet sand.

Step 4

Make the cake: Combine the milk, the vanilla and the eggs in a jug and mix with a fork just to break down the eggs. Add about three-quarters of the wet ingredients in the bowl and beat on medium to medium-high speed for 2 minutes, scraping the bowl halfway. You will see the mixture to lighten in color and get fluffier. Add the rest of the wet ingredients and beat for another 30seconds until well combined. Add the green food coloring (if using) and mix well.

Step 5

Bake: Divide mixture into two pans and bake for 40-50 minutes or until a toothpick inserted in the center comes out clean. Invert onto a rack and let the cakes cool.

Step 6

Make the buttercream: For the buttercream, beat the butter and 3 1/2 cups sugar on low speed until well incorporated. Increase speed to high and beat well for 3-4 minutes until very fluffy. Add the salt, the vanilla, the food coloring, and two tablespoons rosewater and beat to incorporate. Taste the buttercream and add more sugar or rosewater to your preference, until you get the consistency you want.

Step 7

Assemble the cake: When cakes are completely cooled, frost with buttercream and decorate with chopped pistachios.