Pistachio Cake with Pudding Mix

Calling all pistachio lovers! You will adore this light and fluffy Pistachio Cake with Pudding Mix. Also known as Watergate Cake, this cake is moist and tender, with a cool and creamy pistachio frosting.

slice of pistachio cake topped with pistachio frosting and chopped pistachios on a white plate.

This Pistachio Cake with Pudding Mix is a classic. The recipe was created in the early 1970s, just before Pistachio Salad.

In some cookbooks, this cake is called Watergate Cake (more on that below!).

The recipe uses TWO boxes of pistachio pudding mix: one for the cake and one for the frosting. I love that it creates this lovely green hue, which is perfect for St. Patrick’s Day, Christmas, or really anytime that pistachio craving hits.

When topped with the sweet and creamy pistachio frosting, this cake is truly a pistachio lover’s dream.

Jump to:
whole pistachio cake topped with green pistachio frosting and chopped pistachios.

Why is pistachio cake called watergate cake?

There are several theories on why Pistachio Cake is called Watergate Cake. According to this history on Watergate Salad, one theory is that pistachio pudding mix debuted in June 1972, the same month as the Watergate break-in.

Another theory is that it’s called Watergate Cake “because of all the nuts that are in it.” LOL!

Top tips

  • Traditional recipes for this cake call for walnuts in the cake (which were likely easier to purchase in the 1970s). I swapped in pistachios to amp up the pistachio flavor, but you can can substitute walnuts if you prefer.
  • Don’t have Sprite? Use 7-Up or any lemon-lime soda instead.
  • If you want the cake to be extra green, add a few drops of green food coloring to the cake batter. (I did not do this—the photos you see is the actual color of the cake/frosting.)
  • Leave time for the cake to sit in the refrigerator for at least 30 minutes before serving. This allows the frosting to set up a bit more.


white cake mix, pistachio pudding mix, and other cake ingredients on a white table.e

Be sure to check the recipe card below for a full list of ingredients and instructions!

  • White cake mix is the base of this recipe (that’s what I used). Yellow cake mix works, too.
  • You’ll need TWO boxes of instant pistachio pudding mix—one for the cake and one for the frosting. Do NOT use cook & serve pudding here. You need the instant variety.
  • Sprite (or 7-Up) makes the cake extra fluffy.

How to make Pistachio Cake with pudding mix

Start by greasing a 13×9 inch pan with cooking spray.

Then, combine the white cake mix, one box of instant pistachio pudding mix, 1 cup of Sprite, 3 eggs, and 1 cup of oil in a large bowl. Beat on medium speed for 2 minutes.

Then, stir in the pistachios.

green cake batter in a glass bowl with a handheld mixer.

Spread the cake in the prepared pan, and bake at 350°F for 30–35 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool completely before making the frosting.

For the frosting, whisk the milk and the remaining box of pistachio pudding mix until smooth. Let the mixture sit for 5 minutes to firm up a bit.

Then, fold in the Cool Whip (or another brand of whipped topping).

green fluffy cool whip frosting in a glass bowl with a yellow spatula.

Pour the mixture over the cooled cake, then sprinkle with more chopped pistachios.

Cover and refrigerate for at least 30 minutes, or until the frosting has firmed up a bit.

Slice into squares and serve.

metal spatula lifting a slice of pistachio cake out of a metal pan.

Made Ahead Instructions

Pistachio Cake is perfect for making ahead of time. It needs at least 30 minutes to chill in the refrigerator after frosting anyway, which you can extend to an entire day if you’d like.

I recommend putting a layer of aluminum foil over the top before you place it in the refrigerator. Serve the cake within 24 hours of making it (it’ll start to dry out a bit after that), but the cake will last in the refrigerator for up to 5 days.

You can also freeze this cake for up to 3 months.

slice of pistachio cake with a bite taken out, sitting on a white plate.

More old fashioned cakes

I LOVE a good 13×9 inch cake recipe! Here are a few more of my favorites.

📖 Recipe

slice of pistachio cake topped with pistachio frosting and chopped pistachios on a white plate.

Pistachio Cake with Pudding Mix

Published by Kate
Pistachio lovers will adore this pistachio cake, topped with a cool and creamy pistachio frosting. Instant pudding mix creates the delightful green hue!
4.89 from 17 votes
Prep Time 15 minutes
Cook Time 35 minutes
Refrigeration time 30 minutes
Total Time 50 minutes
Course Dessert
Cuisine American
Servings 15 servings
Calories 409 kcal


For the cake:

  • 1 package white cake mix
  • 1 package (3.4 oz) instant pistachio pudding mix
  • 1 cup lemon-lime soda (like Sprite or 7-Up)
  • 1 cup vegetable oil
  • 3 eggs
  • ½ cup chopped pistachios

For the frosting:

  • cups cold milk
  • 1 package (3.4 oz) instant pistachio pudding mix
  • 1 carton (8 oz) whipped topping, thawed
  • ¼ cup chopped pistachios


  • Preheat oven to 350¨F. Grease a 13×9 inch baking dish with cooking spray.
  • In a large bowl, combine the white cake mix, 1 package of pudding mix, soda, vegetable oil, and eggs. Beat with a hand mixer on medium speed for 2 minutes. Stir in ½ cup chopped pistachios.
  • Pour into the prepared baking dish. Bake for 30–35 minutes, or until a toothpick inserted into the center comes out clean.
  • Allow the cake to cool completely.
  • Once the cake is cool, place the milk and the remaining package of pudding mix in a large bowl. Whisk until smooth. Let sit for 5 minutes (the pudding will firm up a bit). Then, fold in the whipped topping.
  • Spread the frosting on top of the cake. Sprinkle with chopped pistachios. Refrigerate for at least 30 minutes before serving to allow the frosting to firm up slightly.
  • Cut into slices and serve. Store any remaining cake in the refrigerator.


Make sure you are using instant pistachio pudding (not cook & serve). 
Want an extra green cake? Add a few drops of green food coloring to the cake batter and/or the frosting. (I did not do this—the color that you see in the photos is from the pudding mix only.)
You can replace the pistachios with chopped walnuts, if you’d like. 
The cake will keep for up to 5 days in the refrigerator. You can also freeze the cake for up to 3 months. 
You can make this into a layer cake by using two 9-inch cake pans. Bake the cakes for 20–25 minutes. You can also make it in a bundt pan (bake for 45–50 minutes). 


Calories: 409kcalCarbohydrates: 48gProtein: 5gFat: 22gSaturated Fat: 6gPolyunsaturated Fat: 10gMonounsaturated Fat: 6gTrans Fat: 0.3gCholesterol: 36mgSodium: 463mgPotassium: 150mgFiber: 1gSugar: 34gVitamin A: 124IUVitamin C: 0.3mgCalcium: 130mgIron: 1mg
Keyword pistachio cake
Did You Make This Recipe?Please leave a star rating and comment below!

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  1. 5 stars
    this is one of my favorite cakes. I use heavy whipping cream for the frosting instead of cool whip. it holds up great in the refrigerator and is so light and fluffy my family ask me to make this as a birthday cake for them! I use white cake mix as well because I find the white gives off a better color with the pistachio pudding plus I feel it’s a fluffier cake! good luck and enjoy I’m sure this recipe will be one of your favorites too!

    1. Thanks for sharing your take on the recipe—that’s great to know that whipping cream holds up well!

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