Impossibly easy and moist gluten free chocolate zucchini cake recipe mixes together in one bowl, versatile as a sheet or layer cake, and has a rich velvety frosting to make this one of best zucchini desserts ever!

Best gluten-free zucchini cake!
Since summer means either an abundance of zucchini in the garden or farmer’s market, I am no stranger to making my fair share of gluten free zucchini recipes. This chocolate zucchini cake has been deemed as one of the best gluten free dessert recipes because, when serving, I’m the only one who knows it’s GF!
Ingredients needed
Just like my gluten-free chocolate cake recipe or vanilla gluten-free cupcakes, the ingredients are simple and readily available in many home cooks’ kitchens. It requires three cups of grated zucchini, which equals about 2 medium zucchini.
Flour – My preferred brand of gluten free all-purpose flour is Cup 4 Cup, but King Arthur Measure-for-Measure also performs well. Both of these flour mixes do contain xanthan gum.
Sugar – Granulated sugar builds the structure in the cake, so it may be reduced slightly, but no more than 1/2 cup.
Eggs – The recipe requires four eggs, which is more than typical cake recipes. This helps with lift and structure. Since zucchini recipes can be dense due to extra moisture, adding an additional egg or two offsets this.
Oil – Like gluten free zucchini bread, oil works better than butter in zucchini recipes. It requires no creaming or mixing, and the neutral flavor helps the chocolate shine through.
Sour Cream – To reduce the amount of oil needed in the cake, I added 1/3 cup sour cream. If you need a dairy free gluten free recipe, simply substitute 1/3 cup unsweetened applesauce or use 1/3 cup more oil.
Unsweetened Cocoa Powder – If you love a darker chocolate flavor use dutch-processed cocoa powder for the cake and chocolate frosting. For most chocolate cake recipes, including gluten-free chocolate cupcakes, natural and dutch processed cocoa powder may be used interchangeably, as long as there is baking powder in the recipe.
How to make Gluten-free zucchini cake
(Note: This is a step-by-step tutorial with pictures. For more specific instructions, along with ingredient amounts, see the recipe card at the bottom of the post.)
- First whisk together the dry ingredients – flour, sugar, cocoa, baking soda, baking powder, and salt. If using a mixer, mix on low speed until combined.
- Next add the eggs, oil, sour cream, and vanilla. Mix well using a mixer on medium speed. The batter will be very thick.
- Fold in the grated zucchini and mini chocolate chips until evenly distributed.
- Pour in a greased 9X13-inch pan (see recipe notes for layer cake instructions), and bake at 350ºF for 50-60 minutes.
- Cool the cake completely before spreading on the easy chocolate frosting.
zucchini cake frosting
Included with the cake recipe is an easy chocolate frosting with a touch of sour cream added for a bit of tanginess. However, there are other options to slather on zucchini cake!
- Fluffy Chocolate Buttercream
- Chocolate Whipped Cream Frosting
- Fluffy Vanilla Buttercream
- Cream Cheese Frosting recipe from 4th of July Brownies
should grated zucchini be dried first?
Larger zucchini contains more moisture, so like in gluten-free zucchini cookies, you may want to squeeze some of the moisture out of the grated zucchini using paper towels before adding. If it is a very large zucchini, the seeds may also be scraped out before grating.
However, if you are using small or medium zucchini, do not squeeze it out before adding or you will have a dry cake!
adding chocolate chips
If you want to keep the cake dairy free, save calories, or don’t have any on hand, the chocolate chips may be omitted.
I use mini chocolate chips because they do not sink to the bottom of the cake. Plus, they disperse evenly, leaving little burst of melted chocolate throughout.
layer cake adaptions
Instead of sheet cake baked in a 9X13-inch pan, it may be poured into two 9-inch cake pans, but they need to be at least 2-inches high. The cake rises pretty high and you don’t want to make a mess in your oven!
The cake layers will have a much shorter baking time, about 25-30 minutes, rotating halfway through. Insert a toothpick in the middle to make sure it is cooked through.
dairy-free modifications
If you need a dairy free gluten free cake, simply substitute 1/3 cup unsweetened applesauce or use 1/3 cup more oil for the sour cream. Omit the chocolate chips or use dairy-free chocolate chips instead.
For the frosting, replace the butter with plant-based butter sticks, such as Earth Balance, but omit the salt in the recipe. Forgo the sour cream and add an additional tablespoon of dairy free milk.
storing and freezing
After cooling and frosting, store gluten free zucchini cake covered, at room temperature, up to 3 days. Do not refrigerate the cake because it will dry it out.
To freeze, place the cake in the freezer until the frosting is solid. Then, wrap securely in plastic wrap and finish with a layer of foil. Leftover slices may also be frozen, individually wrapped in plastic wrap and places in a ziplock freezer bag.
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Moist Gluten Free Chocolate Zucchini Cake
Equipment Needed
Ingredients
- 2 cups gluten free all purpose flour, I use and recommend Cup 4 Cup
- 2 cups granulated sugar
- ¾ cup unsweetened cocoa powder
- 2 teaspoons baking soda
- ½ teaspoon baking powder
- ½ teaspoon salt
- 4 large eggs
- 1 cup canola oil
- ⅓ cup sour cream, see recipe notes for dairy-free substitution
- 2 teaspoons vanilla extract
- 3 cups grated zucchini, about 2 medium
- 1 cup (optional) mini chocolate chips
Chocolate Frosting
- 5 tablespoons unsalted butter, softened
- 3 cups powdered sugar, divided
- ⅓ cup unsweetened cocoa powder
- 2 tablespoons sour cream
- ¼ teaspoon salt
- ¼ cup milk
Instructions
- Preheat the oven to 350°F. Grease a 9X13 inch pan with nonstick cooking spray and set aside. See recipe notes for using 9-inch layer cake pans.
- In a large bowl whisk together the dry ingredients – flour, sugar, cocoa, baking soda, baking powder, and salt. If using a mixer, mix on low speed until combined.
- Add the eggs, oil, sour cream, and vanilla. Mix well, using a mixer on medium speed. The batter will be very thick.
- Fold in the grated zucchini and mini chocolate chips until evenly distributed. Pour into the prepared baking pan.
- Bake for 50-60 minutes, rotating pan halfway through. Use a toothpick inserted in the middle to test if the cake is done. Cool completely before frosting.
Chocolate Frosting
- In a large bowl beat together the softened butter, 2 cups powdered sugar, cocoa powder, sour cream, and salt until the powdered sugar is mixed in.
- Add the milk and additional 1 cup powdered sugar. Beat on high speed for 1-2 minutes, or until well combined and fluffy. Spread on cooled cake.
- DID YOU MAKE THIS RECIPE?? DON'T FORGET TO LEAVE FEEDBACK AND RATE BELOW!
Recipe Notes
layer cake directions
Pour into two 9-inch cake pans, but they need to be at least 2-inches high. The cake rises pretty high and you don’t want to make a mess in your oven! The cake layers will have a much shorter baking time, about 25-30 minutes, rotating halfway through. Insert a toothpick in the middle to make sure it is cooked through.Dairy-Free Adaptations
Omit the chocolate chips or use dairy-free chocolate chips instead. For the frosting, replace the butter with plant-based butter sticks, such as Earth Balance, but omit the salt in the recipe. Forgo the sour cream and add an additional tablespoon of dairy free milk.Storing / Freezing
After cooling and frosting, store covered, at room temperature, up to 3 days. Do not refrigerate the cake because it will dry it out. To freeze, place the cake in the freezer until the frosting is solid. Then, wrap securely in plastic wrap and finish with a layer of foil. Leftover slices may also be frozen, individually wrapped in plastic wrap and places in a ziplock freezer bag.Nutrition
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Sara 2K says
Followed recipe as written (used cup4cup) – delicious! One of the best GF cakes we’ve made. The frosting really makes it!
Melissa Erdelac says
I really appreciate this, Sara! Thanks so much for dropping me a line!
Best,
Melissa
Dawn says
Made this chocolate cake this morning, but added one more egg as my batter looked dry. (Size of large eggs can be deceiving) I used a 9 x 13 pan and it did rise high. I was a bit worried about my cook time because at some point my oven got turned off. I turned it back on and baked it a bit longer. Just ate a piece slightly warm. Moist and delicious!
Elyssa Caterini says
This is amazing recipe! just made it for a family birthday party and everyone LOVED it. It is super moist and chocolatey.
Melissa Erdelac says
Thank you, Elyssa! I appreciate you taking the time to let me know. Makes me so happy!
Best,
Melissa
Sad says
I made this recipe and it turned out really terrible. I was suspicious of the ratios the whole time. The batter was so so so dry (which your recipe mentions) but once it was baked it had the worst texture/flavor.
Melissa Erdelac says
I’m so sorry to hear that! I haven’t had experience with what you are describing. I wish I could help more. What brand of GF flour did you use?
Best,
Melissa
Lisa says
OMG! This is absolutely delicious! Moist and rich! I halved the recipe and baked in 8×8. I used Bob’s Redmill 1:1 baking flour. Gonna make this again, and again.
Melissa Erdelac says
Yay! This makes me so happy! Thank you for taking the time to let me know!
Best,
Melissa
Sara K says
So yummy! I can’t believe I’m saying this but I think I wouldn’t use all the frosting next time – was a bit too sweet (and I used 1/2 cup less sugar in the cake than was called for – otherwise followed recipe as written). It came out of the oven so puffed up and fell a bit after it cooled – is that to be expected?
Melissa Erdelac says
Hi Sara,
Perhaps the oven runs a little hot? If it rises too quickly it will fall. But, nothing that can’t be fixed with a little frosting over top, right?? 🙂 Glad you enjoyed the cake.
Best,
Melissa
Anna Carman says
The Best Chocolate zucchini cake ever. My husband says it’s pretty hard to beat that cake. Can’t even believe it’s gluten free. Wow!
Melissa says
Thank you, Anna! I’m so glad the recipe was a hit with you and your husband! Thanks for taking the time to write!
Best,
Melissa
Anonymous says
Tooo much baking soda
Mary Murphy says
Best Gluten Free Chocolate Cake ever. Followed the recipe to a T and it was perfection !!
Melissa says
Yay! So glad to hear, Mary! Thanks for taking the time to let me know.
Best,
Melissa
Rose says
Please list the salt amount in the ingredients. Thanks!
This cake is delicious!!
Melissa says
Hi Rose,
Thank you so much for pointing that out! All fixed now 🙂 Glad you enjoyed the cake!
Best,
Melissa
Momma C says
Best chocolate cake ever! Perfection just as written. Even my friends that aren’t gluten free loved it!!!
Melissa Erdelac says
Thank you so much! This makes me so happy!
Best,
Melissa
Cory says
What do you mean by I recommend 4cup ?just 4 cup gluten free flour or double the whole recipe ?
Melissa says
Hi Cory,
Sorry for the confusion. It’s a gluten free flour brand called Cup 4 Cup. If you tap the link in the recipe card it will take you to the product I use and recommend.
Best,
Melissa