Peanut Butter Zucchini Cake is a moist and dense cake full of peanut butter flavor with even more peanut butter drizzled on top. If you love peanut butter, be sure to try my Peanut Butter Cake with Chocolate Frosting, too!

Peanut Butter Zucchini Cake With Piece Cut

Peanut Butter Zucchini Cake

Don’t worry about seeing zucchini in this recipe title and ingredients; you will not taste it! Zucchini adds so much moisture to muffins and cakes, like my Chocolate Zucchini Muffins and Zucchini Cake. Once you use it, you will be hooked! And this peanut butter zucchini cake is no exception; the crumb is so moist with a strong peanut butter flavor in every bite.

How to Add Zucchini to Cake

Peanut Butter Zucchini Cake Ingredients

Peanut Butter: Use creamy peanut butter for both the cake batter and the topping. For the topping, melt the peanut butter to drizzle over the cooled cake.

Buttermilk: If you don’t have any on hand, make your own homemade buttermilk.

Zucchini: Size matters. A large zucchini will be drier. A small zucchini will have more moisture. Certain recipes work best with different sizes. For instance, I use a medium to small zucchini with this recipe because I want the moisture the zucchini brings, but I use a large zucchini for my Double Chocolate Zucchini Cupcakes. Peel the zucchini for this recipe. And, be sure to remove any seeds if there are any.

Peanuts: For a nutty crunch, I like to add chopped peanuts on top of the peanut butter drizzle. However, you can certainly leave those off the cake if you prefer.

Adding Peanut Butter to Peanut Butter Zucchini Cake

Baking with Zucchini

When using zucchini in recipes there are a couple of tips & tricks that help to make sure your baked goods are perfect!

-Use the fine side of your grater. Coarser pieces will have a slightly more noticeable flavor and texture in a finished cake or bread recipe. 

-Some recipes ask that the zucchini is pressed well with a clean towel to soak up excess moisture or to prevent whatever your baking from getting too soggy. Pay close attention to the recipe that you are making with zucchini as the level of moisture they provide is important. For instance, in this recipe, the zucchini is the main source of moisture and should not be drained. 

Piece of Peanut Butter Zucchini Cake

More Zucchini Treats

5 from 1 vote

Peanut Butter Zucchini Cake

Prep Time 15 minutes
Cook Time 30 minutes
Cooling Time 30 minutes
Total Time 1 hour 15 minutes
Peanut Butter Zucchini Cake is a moist and dense cake full of peanut butter flavor with even more peanut butter drizzled on top.



  • 1 cup (258 g) creamy peanut butter
  • 1 cup (200 g) brown sugar, packed
  • 1 large egg, room temperature
  • 1 teaspoon vanilla extract
  • ¼ cup (61 g) buttermilk
  • cups (187.5 g) all-purpose flour
  • ½ teaspoon kosher salt
  • ½ teaspoon baking soda
  • 1 cup zucchini, peeled, shredded, and undrained with no seeds (small to medium size)


  • ½ cup (129 g) creamy peanut butter, melted
  • chopped peanuts, optional


  • Preheat oven to 350°F and grease a 9-inch round cake pan.
  • In a large bowl, mix together the peanut butter, brown sugar, egg, vanilla extract, and buttermilk until well combined.
  • Add the flour, salt, and baking soda to the peanut butter mixture. (The batter will be dry, but the undrained zucchini will bring in moisture.)
  • Fold in the shredded, undrained zucchini.
  • Pour the batter into the prepared cake pan and bake for 25-30 minutes, or until an inserted toothpick comes out with a few crumbs, but no wet batter.
  • Let the cake cool before adding the melted peanut butter and chopped peanuts (optional).

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Meet Amanda Rettke

Amanda Rettke is the creator of I Am Baker, and the bestselling author of Surprise Inside Cakes: Amazing Cakes for Every Occasion – With a Little Something Extra Inside.Over the course of her 15+ year blogging adventure, she has been featured in and collaborated with the Food Network, New York Times, LA Times, Country Living Magazine, People Magazine, Epicurious, Brides, Romantic Homes, life:beautiful, Publishers Weekly, The Daily Mail, Star Tribune, The Globe and Mail, DailyCandy, YumSugar, The Knot, The Kitchn, and Parade, to name a few.

Reader Comments

  1. thank you, best kind of zucchini cake, I’ve always only really made zucchini bread, over and over and over, so this is a nice change! It’s one of those unexpected ingredients that makes perfect sense

  2. Made this for a family gathering and it was a hit. I topped it with a peanut butter ganache instead though and it was so good.the cake was moist and delicious.

  3. I made the peanutbutter zucchini cake today. Doubled the reciepe as I have so much zucchini. Chose to top it with boiled chocolate frosting. I will let you know how it turned out ..

    1. No it wasn’t. 🙂 This cake is one of the most tested & perfected recipes on my website. The ONLY way to get those results were if you failed to add the zucchini.

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