This incredibly tender decadent dark chocolate cake is topped with a creamy peanut butter frosting making one of my favorite flavor combination. Special dark cocoa powder along with dark chocolate chips make this a chocoholics dream cake. Peanut butter chips and a thick blanket of peanut butter buttercream complete this amazingly rich cake.

Last week I was treated to a big bag of fresh produce from a dear friends garden. In the bag hidden under layers of green beans, peppers and beautiful heirloom tomatoes, I discovered a half dozen rather large zucchini. I was aware that my friend was going to include some squash in along with the other goodies, but found it fun that there were so many. Anyone who grows a garden knows how once the squash start producing, you wonder why you planted so many plants.

While we enjoyed some of the zucchini fresh in salads and grilled, I found I still had quite a bit left. So I started thinking about a making bread or a cake. Then I recalled one of the best brownies I had ever tasted that was made with zucchini and decided to make a chocolate treat. This cake turned out incredible! So moist and tender, and with an amazing dark chocolate goodness. This cake certainly would not require any frosting or icing, however when I was getting the chocolate chips for the cake out of the pantry, I came across a cup of peanut butter chips I left over from something, and my inspiration was born.

A potato ricer makes easy work of squeezing the excess water out of the fresh grated zucchini.

Preparing the zucchini for the cake is really easy. I like to peel the squash especially if they are larger, the skin becomes tough and bitter. If the zucchini are rather large they also might contain seeds, in that case halve the squash and use a spoon to remove. A food processor fitted with a shredding blade can make quick work of preparing the vegetable however I usually find the box grater just as easy and less to clean. I have found that the best way to remove the excess liquid from the squash is by using my potato ricer. I fill the cup about half-way with the shredded squash and squeeze hard. You can also use a clean kitchen towel to wring out the water, or place the shredded product in a wire strainer and use the back of a spoon to remove the water.

The batter for this cake will be quite thick but this will compensate for the water in the zucchini during baking.

Regular or natural peanut butter work equally well for this frosting however the natural butters tend to make a bit of a grainy texture.

The peanut butter frosting for this cake could not be much easier. Any kind of peanut butter will work for this recipe, smooth or chunky is really is all a personal preference or just simply use what you have in the cupboard. I had a jar of natural Skippy creamy that I used for this cake. I have experimented in the past with different kinds of peanut butter for this frosting and found the only difference was that the natural butters create a bit of a grainy texture in the finished product. So if you are wanting an extra-creamy butter cream I would suggest not using one of the natural butters.

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Dark Chocolate & Peanut Butter Zucchini Cake

Decadent, moist and rich dark chocolate cake topped with a creamy peanut butter frosting. Using shredded zucchini from the garden.

Course Cakes, Dessert

Cuisine American

Keyword chocolate cake, zucchini cake

Prep Time 20 minutes minutes

Cook Time 1 hour hour

Servings 12

Author Christoph

Equipment

• Hand mixer

Ingredients

For the cake:

• 1 ¼ cups all-purpose flour
• ½ cup Hershey’s Special Dark cocoa powder
• 1 teaspoon baking soda
• 1 teaspoon instant espresso powder
• ¼ teaspoon salt
• 1 cup sugar
• 1 egg plus 1 egg yolk
• ½ cup butter - melted and slightly cooled
• 1 teaspoon vanilla
• 2 cups grated zucchini – water squeezed out
• ½ cup dark chocolate chips
• ½ cup peanut butter chips

For the Frosting:

• 1 cup peanut butter ***
• 2 tablespoons butter – softened
• 1 teaspoon vanilla
• 1/8 teaspoon salt
• 2 tablespoon heavy cream
• 1 cup powdered sugar – more as needed for consistency
• mini chocolate chips or chocolate curls for decoration if desired

Instructions

Cake:

• Position rack in the center of oven and heat to 350°F. Grease a 9 x 5” loaf pan and line with parchment paper.
• In a medium-sized mixing bowl sift together Flour, cocoa powder, baking soda, espresso powder, and salt.
• In a separate mixing bowl, beat together sugar and eggs until pale and creamy. Mix in butter and vanilla. Stir in zucchini and mix until completely incorporated.
• Mix the dry ingredients in to the wet. Mix only enough to completely combine. Batter will be thick.
• Spread into prepared pan and bake for 50 to 60 minutes. Baking time will vary depending on the wetness of the zucchini. Test with a tooth pick or knife.
• Remove from oven and let stand in the pan for 5 minutes before moving to a wire rack to completely cool before frosting.

Frosting:

• Cream together peanut butter and butter. Beat in vanilla, salt, and cream. Add powdered sugar slowly and mix. If needed add more powdered sugar.
• Spread over cooled cake and top with chocolate chips or curls if desired.

Notes

Squeeze as much water as possible out of the shredded zucchini. I find a potato ricer works extremely well.

 

***Either creamy or smooth work well, your choice. Natural peanut butters make the frosting a bit grainy but equally as tasty. 

A combination of flavors that is undeniably hard to beat is chocolate and peanut butter, and this cake definitely brings the two favorites together to create one stunning treat. Moist chocolate cake is covered with a creamy rich peanut butter frosting and layered with chopped Reese’s peanut butter cups, then topped with a dark chocolate gananche. A sweet tooth’s dream come true.

I finally broke down and treated myself to some 6″ x 3″ cake pans. I had been wanting some for a while, and I guess I just needed a good excuse. If you have not tried Fat Daddio’s bakeware, I strongly recommend it! High quality and very reasonable prices.

Any cake whether it is made from scratch or from a box, can be baked in any size pan, assuming you have enough batter. Below is a chart I have assembled that lists some common pan sizes, the amount of batter you need to fill them, the recommended baking temperature and time. I find it rather handy. There is a link below the chart if you would like to print it out for future reference.

Printable PDF of chart: Layer Cake Baking Times & Temps

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Chocolate & Peanut Butter Cake

A combination of flavors that is undeniably hard to beat is chocolate and peanut butter, and this cake definitely brings the two favorites together to create one stunning treat. Moist chocolate cake is covered with a creamy rich peanut butter frosting and layered with chopped Reese’s peanut butter cups, then topped with a dark chocolate gananche. A sweet tooth’s dream come true.

Course Dessert

Cuisine American

Prep Time 30 minutes minutes

Cook Time 40 minutes minutes

Total Time 1 hour hour 10 minutes minutes

Servings 16

Ingredients

Cake

• 2 cups all-purpose flour
• 2½ cups sugar
• ¾ cup dark cocoa powder
• 2 teaspoons baking soda
• 1 teaspoon salt
• 1 cup vegetable oil
• 1 cup Greek yogurt
• 1½ cups water
• 2 tablespoons white vinegar
• 1 teaspoon vanilla extract
• 2 eggs

Peanut Butter Frosting

• 2 cups creamy peanut butter
• 4 cups confectioners sugar
• 1 cup unsalted butter
• 2 Tablespoons vanilla extract
• ¾ teaspoon salt
• ½ cup heavy whipping cream
• 1½ - 2 cups chopped Reese’s Peanut Butter cups filling and garnish

Chocolate Ganache

• 2 cups dark chocolate chips
• 1 cup heavy whipping cream
• 1½ teaspoons instant Espresso coffee

Instructions

Chocolate Cake

• Heat oven to 350°F.
• Grease cake pans with butter or spray (no need for flour with this recipe). Line the bottom of the pan with a parchment paper and lightly grease the paper.
• In the bowl of a stand mixer, whisk together all dry ingredients.
• On low-speed, add the oil and yogurt, mix to combine.
• Slowly add water, vinegar, and vanilla.
• Add the eggs one at a time. Increase to medium speed and beat mixture until completely combined about two minutes, scraping the sides of the bowl occasionally.
• Divide evenly among pans.
• Bake for the recommended time for the pan size you are using (see chart above). Cakes are done when the center springs back when lightly touched. You can also test your cakes by inserting a tooth pick in the center.
• Let the cakes cool in their pans for about 20 minutes before removing them. Place on a wire rack to completely cool.

Peanut Butter Frosting

• Cream together peanut butter, butter and powdered sugar using the paddle attachment of a stand mixer.
• Add salt and vanilla.
• Slowly add whipping cream.
• Mix on medium-high speed for 3 – 4 minutes or until frosting is light a fluffy.
• Assemble
• Level the cakes with a sharp knife and cut into more layers if desired (I cut each layer in half to create four).
• Place a small dollop of frosting on the center of a cake round or plate (this will prevent the cake from sliding).
• Place first layer on cake, spread with an even coat of frosting. Sprinkle evenly with chopped Reese’s cups. Add next layer and repeat.
• Frost the top and sides of the cake. Allow frosting to set up for several hours before adding the ganache.

Ganache Topping

• Place chocolate chips in a medium-sized mixing bowl.
• Heat cream just to the point of boiling either on the stove or in the microwave. Pour hot cream over chips and allow to stand for several minutes. Using a whisk slowly stir cream and chips. The heat of the cream will melt the chips.
• Mix until completely smooth.
• Add espresso powder and mix well.
• Allow to stand. Ganache will thicken as it cools.

Finishing Touches

• Let the ganache cool until it starts to thicken but still pour-able. Pour on to center of cake. Using a small spatula spread the ganache evenly towards the edges of the cake allowing some to flow down.
• Add more chopped peanut butter cups on top and drizzle with ganache.
• Allow cake to set up several hours before cutting.
• Keep uneaten cake in the refrigerator.

Notes

While I really enjoy making my own cake from scratch, you could most certainly use a boxed cake mix in the interest of time. I usually like to bake my cakes the day before I assemble them. Once they are completely cool, I wrap them in plastic wrap and hold until I am ready to put it all together. This really makes the project much easier than doing everything at once.

Cake recipe adapted from the Smitten Kitchen. Frosting recipe courtesy Smells Like Home.