Preheat oven to 350 degrees Fahrenheit and butter or PAM spray a 13x9 inch pan
Beat cake mix, sparkling water, oil, eggs, 1 package of the pudding mix, 1/2 tsp salt, cardamom powder, and crushed saffron until the mixture gets light fluffy.
Toss in the crushed pistachio and coconut flakes and fold them in the mixture using a spoon.
Pour the mixture into the PAM and bake 25 to 30 mins until the center is baked. Take the cake out of the oven and let it completely cool at room temperature.
While the cake is cooling, make the frosting by beating heavy whipping cream until it starts to thicken a little. Then add sugar, 3 tablespoons of the pudding powder and 1/2 tsp of salt. Beat until a thickened, smooth icing is made.
Spread the icing onto the cake and add additional crushed pistachios if desired for garnish.
Store in the fridge for up to 5 days (if it even lasts that long! :))