Gluten Free Zucchini Chocolate Cake

This fudgy gluten free zucchini chocolate cake is moist, decadent and the best way to use seasonal zucchini! Spoiler - you'll probably not be able to tell it's packed with veggies. And don't skip the dreamy chocolate ganache icing!

Easy Chocolate Zucchini Cake Recipe

Chocolate and zucchini is a classic if unexpected pairing for cake, and this gluten free chocolate zucchini cake ticks all the boxes: a dense, moist cake, loads of chocolate, a fudgy cap of ganache icing, and a secret ingredient: zucchini. It's a fantastic way to use up all that squash that's bursting out of your garden in late summer, but stands on its own as a stellar gluten free chocolate cake.

I've written about chocolate zucchini cakes before (you can see my recipe for a chocolate zucchini cake made with all-purpose flour in this post), but this gluten free version tops all. It's inspired by King Arthur Flour's chocolate zucchini cake recipe and makes a large, luscious 9x13-inch pan of cake. A simple blend of whole grain oat and almond flour keeps the cake naturally gluten free, and a bit of buttermilk adds tangy moisture.

The magic of gluten free zucchini chocolate cake is that you'd hardly know there is any zucchini in it, yet it adds a certain something to the cake you won't find in a more traditional chocolate cake. And for those who may not love zucchini in its natural state (ahem, my kids), making this cake is a lovely way to get in some veggies along with the cake.

For another take, see my gluten-free chocolate zucchini cake recipe that features teff flour.

Why You'll Love It

Chocolate zucchini cake is a classic! It's such a great way to use squash when you've made too many gluten free zucchini bread loaves or batches of banana zucchini muffins and need something a little different. This is definitely a dessert recipe, and it's meant to be shared. Here's why you'll love it:

• Easily made gluten free: Yes! You only need two simple gluten free flours to make chocolate zucchini cake. Oat flour and almond flour combine for a sturdy, cake-y crumb.
• So chocolatey. As its name implies, gluten free zucchini chocolate cake is so rich and full of chocolate. You'll use ¾ cup of cocoa powder in the cake for pure chocolatey goodness, and have I mentioned the icing? It's a simple ganache made with semisweet chocolate and it's out of this world.
• Great way to use zucchini. If you're a gardener, you may be looking for a way to use up all your summer squash! This cake is perfect, especially if you've had your fill of gluten free zucchini bread and gluten free zucchini muffins.
• Makes a lot. Take out your 9x13 inch pan and make this cake for a crowd! You'll have a huge, gorgeous amount of cake to serve at your next summer barbecue.

Ingredient Notes

Here's a quick overview of what you'll need to make this gluten-free chocolate zucchini cake. You'll find the full ingredient amounts and instructions in the recipe card at the end of this post.

• Butter - Use unsalted, room temperature butter as the base of the cake.
• Vegetable oil - You can use olive oil or another neutral oil like avocado oil if you wish.
• Granulated sugar - Try a combination of brown sugar and granulated sugar if you like. You can also reduce the amount of sugar by ⅓ cup for a less-sweet cake.
• Leavening - A combo of baking powder and baking soda helps the cake to rise.
• Salt - I always use fine sea salt.
• Eggs - I used large eggs when testing this recipe, so I recommend using large eggs in your home kitchen as well.
• Buttermilk
• Oat flour - Naturally gluten free oat flour adds structure to the cake. A good substitution is teff flour if you can't eat oats.
• Almond flour - If you don't eat almonds, try another nut flour of choice or swap brown rice flour.
• Cocoa powder - Always use unsweetened cocoa powder so that it doesn't overwhelm the cake with sweetness.
• Zucchini - No need to peel the zucchini before shredding it, but give the zucchini a good wash beforehand.

Icing

• Chocolate chips - I prefer semisweet chocolate chips or chopped chocolate for the icing, though if you like a sweeter, richer touch you can use milk chocolate chips.
• Heavy cream - If needed, substitute half-and-half with similar results.

How to Make Gluten Free Zucchini Chocolate Cake

Here's a quick look at the steps you'll use to put together this beautiful cake:

• Prep: Lightly grease a 9" x 13" pan.
• Cream butter: In a large bowl, beat together the butter, oil, sugar, baking powder, baking soda, and salt until smooth.

• Add eggs: Beat in the eggs.

• Add flour and buttermilk: Beat in the oat flour, then the buttermilk, then finish by beating in the almond flour.

• Add cocoa powder: Mix in the cocoa powder until smooth.
• Add zucchini: Fold in the zucchini.

• Rest batter: Spoon the batter into the prepared pan then rest the batter for about 20 minutes. Preheat the oven to 325°F.
• Bake cake: Bake the cake for about 50-60 minutes, then cool completely in the pan.

• Make icing: Combine the chocolate and cream.
• Melt: Heat until the chocolate softens, then stir to mix in the the chocolate.

• Ice the cake: Spread the icing evenly over the cooled cake.

How Should I Shred My Zucchini?

Similar to other zucchini baking recipes, you won't need to peel the zucchini before adding it into the batter. Just give it a wash and trim the ends before beginning to grate it. I do a coarse grind on my box grater for this cake, but if you would like the zucchini to melt into the batter a bit more, you could use a fine grate. This way you're guaranteed that it will fully disappear. You could also use a food processor to grate the zucchini: Use the grating attachment to process the trimmed zucchini until it's finely grated.

Recipe Tips & Substitution Suggestions

If you need to make some changes to this chocolate zucchini cake recipe, no problem. I've outlined a few simple substitution options below, along with some recipe tips.

• Oat flour substitute - Try brown rice flour, teff flour, or sorghum flour by weight.
• Almond flour substitute - You can use another nut flour, brown rice flour, or tiger nut flour.
• Use 1:1 baking flour: To keep it even easier, use 300 grams of your favorite 1:1 gluten free all-purpose baking flour, or use my easy homemade gluten free flour blend.
• Make it dairy-free - Use dairy-free yogurt for the buttermilk or add 1 teaspoon of vinegar to a non-dairy milk of choice. For the icing, use coconut cream instead of the cream.
• Other icing choices - You can make the ganache as written (recommended by me!) or swap it with a simple chocolate glaze. You can also sift powdered sugar over the top.
• Rest the batter - As always, gluten free cake batters very much benefit from a 20-30 minute rest after they've been assembled but before baking. This allows the gluten free flours to fully hydrate, making the finished cake taste so much better!
• Refined sugar-free - Substitute coconut sugar for the sugar in the cake.
• Egg-free - I haven't tested this recipe with an egg substitute, but you could try using flax eggs instead of the eggs.
• Make a layer cake - Bake the cake in two 9-inch layer cake pans (note that baking time may differ), then fill and frost the cake with your favorite chocolate frosting (may I suggest my recipe for chocolate buttercream?)

Storage Options

Store the cake, well covered, on the counter for up to 2 days. Then transfer it to the fridge and store it for up to 5 days. To freeze, wrap the chilled cake in plastic and place it in a freezer-safe bag, then store it in the freezer for up to 3 months. Thaw the cake in the fridge before serving.

More Easy Gluten Free Chocolate Cake Recipes

• Oat Flour Chocolate Cake
• Gluten Free Chocolate Cake with Peanut Butter Frosting
• The Best Gluten Free Chocolate Cake