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.
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. In both cases it creates this lovely green hue, which is perfect for St. Patrick’s Day, Christmas, or really anytime that pistachio craving hits.
The cake also has one more unique ingredient: a small can of Sprite. The bubbles in the soda act like a leavening agent, making the cake light and fluffy.
When topped with the sweet and creamy pistachio frosting, this cake is truly a pistachio lover’s dream.
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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.”
- 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 is the base of this recipe. 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.
- The frosting is a combination of milk, Cool Whip, and pudding mix. It’s creamy and very light!
- You’ll also need oil and eggs for the cake.
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.
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).
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.
Can I make pistachio cake ahead of time?
Pistachio Cake with Pudding Mix 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.
Frequently Asked Questions
Yes! This recipe can be made in two 9-inch round pans OR a bundt pan. Bake times are 20–25 minutes for round cake pans or 45–50 minutes for a bundt pan.
The pistachio pudding mix will turn both the cake and the frosting light green, but if you want it extra green, add a few drops of green food coloring to both the cake batter and the frosting. The photos you see here do not have any food coloring added—the green hue is from the pistachio pudding mix only.
This cake should be stored in the refrigerator.
No, cook & serve pudding will not work for this recipe. Use instant pistachio pudding mix.
If you don’t have pistachios, you can substitute chopped walnuts instead. Keep in mind that there are little pistachio pieces in the pudding though, so if you have any allergies, I recommend making a different sort of cake (like my Jell-O Poke Cake with lime Jell-O to make it green!).
More old fashioned cakes
I LOVE a good 13×9 inch cake recipe! Here are a few more of my favorites.
- Ding Dong Cake (tastes like a Hostess ding dong)
- No-Bake Banana Split Cake (love this one in the summer)
- Chocolate Mayonnaise Cake (also made with boxed cake mix)
- Coconut Poke Cake (SO moist!)
- Turtle Cake (a must for pecan/chocolate/caramel fans)
- Jell-O Poke Cake (a classic that you can also make green with lime Jell-O!)
Have you tried this recipe? Please leave a ⭐️⭐️⭐️⭐️⭐️ rating and/or comment below!
Pistachio Cake with Pudding Mix
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:
- 1½ 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.