I’m always a big fan of a sheet cake recipe. I love how simple they are to throw together and that they can feed a crowd! The first time I had a Chocolate Zucchini Sheet Cake was at a childhood friend’s house. I remember not really wanting to try it because it had zucchini in it but then loving it when she gave me a slice. You may want to wait to announce that it has zucchini until after your kids have eaten a piece or two. Speaking of sheet cakes, this Raspberry Shortcake Dessert is a must right now with fresh raspberries in season.

It’s funny that I didn’t want to eat that cake as a kid because it had zucchini in it. Now I love zucchini, and it’s one of my favorite vegetables to cook with. I add it to almost every soup I make, and I love to saute it into stir fry recipes. I also love to bake with zucchini and try to always keep some prepped in my freezer. You can check out my post on How to Freeze Zucchini for Baking. It’s super simple and a great way to make use of the extra zucchini you might have in your garden this time of year.

Awesome Zucchini Recipes you’ve got to try!

• Million Dollar Zucchini Skillet
• Zucchini Chocolate Chip Muffins
• Sausage and Zucchini Lasagna Roll-ups
• Zucchini Chocolate Chip Snack Cake
• Banana Zucchini Bread {Bikini Bread}
• Sauteed Zucchini and Yellow Squash with Parmesan Cheese
• 2-ingredient Zucchini Bake
• Chocolate Zucchini Muffins

How to Make Chocolate Zucchini Sheet Cake

1. Preheat oven to 350 degrees. Spray a large 13×18 baking sheet with cooking spray and set aside.
2. Combine the butter and cocoa in a microwave-safe dish and microwave on high for 60-90 seconds or until the butter is melted and hot and can dissolve and activate the cocoa. (It will look nice and dark, kind of like runny melted chocolate.)
3. While the butter and cocoa are in the microwave, measure the sugar out into a large mixing bowl.
4. Stir the hot butter cocoa mixture into the sugar. (This helps cool the butter-chocolate mixture down before you add the eggs.)
5. Add the eggs and vanilla. Whisk well or use a hand mixer to mix it.
6. Add in the buttermilk and, again, whisk or use a hand mixer to thoroughly combine it.
7. Next, mix in the zucchini.
8. Lastly, add the flour, baking soda, and salt. Mix until well combined.
9. Pour batter into the prepared 13×18 baking dish and bake at 350 degrees for 18-20 minutes or until a toothpick inserted in the center comes out clean.
10. Once the cake is baked, you have two choices. You can frost it immediately or you can wait for it to cool. I like to wait until it is mostly cooled.

How to make Fudgy Chocolate Frosting

Frequently Asked Questions about Chocolate Zucchini Sheet Cake

Do I need to squeeze the liquid out of the zucchini before I add it?

You don’t have to squeeze the liquid out. The cake will turn out just fine, but if I feel like the zucchini seems extra saturated with water, I will squeeze about half of it out. When using frozen, grated zucchini after I let it defrost, there is often a lot of water in the bag. I drain out about half of it before adding the zucchini to whatever recipe I’m making.

Should I use a large grate or a small grate for grating the zucchini?

I like to use the small grate when I make this because it is harder for my kids to see the pieces of zucchini. In fact, when you use the small grate, the zucchini pretty much disappears into this cake because the cake is so dark. Another option you can try if you think your kids will freak out if they see zucchini is to put the zucchini in the blender with the eggs and buttermilk to puree it. Then add it to the recipe (see instructions) after you mix the butter mixture with the sugar. Hopefully, that will make sense once you read the instructions for making the cake. 🙂

Can I add chocolate chips?

Yes, definitely! The more chocolate the better; right? Another addition you can make if you want to is adding a 1/4 tsp of ground cinnamon with the dry ingredients. Some people really love what a little cinnamon does for the flavor of this cake.

Will this recipe for Chocolate Zucchini Cake still work if I use a 9×13 pan?

Yes, you can make this Chocolate Zucchini Sheet Cake in a 9×13 baking dish. You will just need to adjust the baking time. It will most likely take 28-30 minutes or possibly longer. The best way to check if the cake is done is to insert a toothpick into the middle of the cake. If the toothpick comes out clean, the cake is done.

Can I make the frosting in the microwave instead of on the stovetop?

Yes. If you want to make it in the microwave, you just put the butter and cocoa in a microwave-safe dish and microwave it for 60-90 seconds or until the butter is melted and hot enough to dissolve/activate the cocoa. Then you can whisk or beat the powdered sugar, vanilla and milk into it until everything is smooth.

What is a good substitution for buttermilk?

My go-to for substituting buttermilk is always a teaspoon of lemon juice per cup of milk. After combining the two, you need to let it sit for 5 minutes before adding it to the recipe. In this recipe, you just need half a cup of milk, so you will only need a 1/2 tsp of lemon juice. You can also use white vinegar if you don’t have lemon juice. I keep lemon juice in my fridge and typically use it for making a buttermilk substitute or sour milk. It’s not worth cutting into a fresh lemon for such a small amount of juice.