This super rich and moist chocolate zucchini cake is topped with the best chocolate frosting—you won't even taste the vegetables!
Recipe by Sally on June 15, 2017
Prep time: PT15M
Cook time: PT30M
Total time: PT3H30M
Rating
4.9 stars ( reviews)
Keywords
chocolate zucchini cake
Ingredients
2 cups (250g) all-purpose flour (spooned & leveled)
3/4 cup (62g) unsweetened natural cocoa powder
2 teaspoons baking soda
1/2 teaspoon baking powder
1 teaspoon espresso powder (optional)
1/2 teaspoon salt
1 cup (240ml) canola or vegetable oil
1 cup (200g) granulated sugar
3/4 cup (150g) packed light or dark brown sugar
4 large eggs, at room temperature
1/3 cup (80g) sour cream or plain yogurt, at room temperature
2 teaspoons pure vanilla extract
3 cups (about 360g) shredded zucchini (lightly blotted; see recipe Note) (2 medium zucchini, about .75–1 lb.)
1 cup (180g) semi-sweet chocolate chips (regular or mini)
1 and 1/4 cups (282g) unsalted butter, softened to room temperature
3 and 1/2 cups (420g) confectioners’ sugar
3/4 cup (62g) unsweetened cocoa powder (natural or Dutch-process)
3–5 Tablespoons (45–75ml) heavy cream (or half-and-half or whole milk), at room temperature
1/4 teaspoon salt
1 teaspoon pure vanilla extract
optional for decoration: chocolate chips and/or chocolate sprinkles
Categories
Dessert
Cuisine
American
Steps
Preheat oven to 350°F (177°C). Grease two 9-inch round cake pans, line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans. (If it’s helpful, see this parchment paper rounds for cakes video & post.)
Whisk the flour, cocoa powder, baking soda, baking powder, espresso powder (if using), and salt together in a large bowl. In another large bowl using a handheld or stand mixer fitted with a paddle attachment, beat the oil, granulated sugar, brown sugar, eggs, sour cream, and vanilla together until combined. Add the zucchini and mix to incorporate. Add the dry ingredients to the batter and beat on medium speed until completely combined. Fold in the chocolate chips. Batter will be slightly thick.
Pour batter evenly into cake pans. Bake for around 28–32 minutes or until the cakes are baked through. To test for doneness, lightly poke the top of the cake with your finger—if it bounces back instead of leaving , the cake is done. Or you can insert a toothpick into the center of the cake—if it comes out clean, it’s done.
Set the cakes on a cooling rack and let cool in the pans for 1 hour. After 1 hour, remove the cakes from the pans, discard the parchment rounds, and let the cakes finish cooling directly on the rack. The cakes must be completely cool before frosting and assembling.
With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy, about 2 minutes. Add confectioners’ sugar, cocoa powder, 3 Tablespoons of cream, salt, and vanilla. Beat on low speed for 30 seconds, then gradually increase to high speed and beat until it’s smooth and creamy. Do not over-whip. Add 1/4 cup more confectioners’ sugar or cocoa powder if frosting is too thin or 1–2 more Tablespoons of cream if frosting is too thick. (I usually add 1 more.) Taste. Add another pinch of salt if desired.
First, using a large serrated knife, slice a thin layer off the tops of the cakes to create a flat surface. Discard (or crumble over ice cream!). Place 1 cake layer on your cake stand, cake turntable, or serving plate. Evenly cover the top with a heaping cup of frosting. Top with 2nd cake layer and spread the remaining frosting all over the top and sides. Pipe any leftover frosting on top. (I used Wilton 1M tip.) Decorate with chocolate sprinkles or chocolate chips if desired. Slice and serve.
Cover leftover cake and store at room temperature for up to 2 days or in the refrigerator for up to 5 days.
Reviews
Alicia on 2026-08-29 (5 stars): Utterly delicious - not exactly a ‘healthy’ cake but at least the zucchini makes you feel a little better about having a second slice :) I actually halved the recipe and it turned out perfectly, and still aimed for a slightly healthier version with a quarter of the recommended sugar (was still plenty sweet enough, especially with a basic chocolate frosting), Greek yoghurt instead of sour cream and olive oil instead of vegetable oil as I quite like that sharper flavour. Half Dutch cocoa and half raw cacao. Cooked in a loaf pan, it took around 45 mins. Yum!
Moriah on 2026-08-31 (5 stars): I made the chocolate zucchini cake as a bundt cake. It was amazingly moist and loved by everyone. I added a little espresso powder to the frosting to give it a deeper taste - it was great. Thank you for your great recipes!
Emily on 2026-09-02 (5 stars): Delicious! Used avocado oil and these were perfect.
Nancy Snavely on 2026-09-02 (5 stars): Baked this for my BD cake today. It came out awesome! It was very forgiving when frosting and decorating, yet it was so moist and flavorful. Didn't change a thing except decreased the sugar in the cake a bit to balance out the American BC. Another hit from SBA! Thank you Sally for making my day so special.
Nancy
Emily on 2026-09-04 (5 stars): My husband said these are the best muffins he’s ever had and he’s not even a fan of chocolate! Absolute perfection!
Lynda on 2026-09-07 (5 stars): My zucchini crop is not doing well this year so I did not have enough to make this cake as is, but I really wanted to try this recipe. Fortunately, the recipe is also in grames, because a half of a 1/3 of a cup would be hard to measure, but 40 gr of sour cream is easy. I made it in a 9X9 square pan. Good crumb and really moist. And half a cake was enough for my guests. Or more reasonable anyway.
Catherine Schreur on 2026-09-07 (5 stars): I made 12 regular cup cakes, 2 large cupcakes, and a loaf from this one recipe. My batter was “snotty” and I was worried, BUT this is fantastic and delicious!!
Deb on 2026-09-08 (5 stars): I honestly can't believe how good this was. Definitely a very rich cake. I guess between the zucchini and the chocolate chips, the cake was almost fudgy! I made it in a 13x9 pan. Honestly added about 4 cups of zucchini, because I wanted to finish what I had. Didn't have espresso powder, but threw about a 1/4 cup of room temp coffee in the mix. Will definitely make again! Hoping to freeze some zucchini to make this in the future. Thank you for a great recipe! I have shared it with friends.
Jan schmude on 2026-09-09 (5 stars): Absolutely the very best zucchini cake ever! So very moist. I'm not a super extreme chocolate lover so swapped out the chocolate frosting for buttercream. Delicious ❤️
Mimi on 2026-09-12 (5 stars): Made absolutely fabulous cupcakes! Was slightly suspicious when I tasted the batter but thought "Sally doesn't lead you down the wrong path!" And wow was I right to trust the recipe! Cupcakes are both light and fudgy at the same time. Good alone, even better topped w Sally's cream cheese frosting.
donna on 2026-09-19 (5 stars): My husband made this for me as my birthday cake this year. He found it easy to make and handle, and it was absolutely delicious. We had so much zucchini from the garden, and that helped it to be very moist. I liked how dark chocolate the cake was. First Rate!
Morgan Nelson on 2026-09-19 (5 stars): Five stars- no notes! Perfection!