Gluten Free Zucchini Chocolate Cake

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 it stands on its own as a stellar gluten free chocolate cake as well.

I've written about chocolate zucchini cakes before, and have made my share of gluten free zucchini bread and gluten free zucchini muffins, but sometimes you just want cake. My version is 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.

Why You'll Love It

Chocolate zucchini cake is an underrated 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 brown rice 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 Should I Shred My Zucchini?

Similar to other zucchini baking recipes, you won't need to peel the zucchini before adding it to 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.