Lemon Blueberry Zucchini Cake with Lemon Frosting

OMG this cake. I first posted it a few summers ago because I knew AK readers were the biggest lemon lovers. This gorgeous lemon blueberry zucchini cake truly took it to the next level — and for good reason too…THIS CAKE IS SIMPLY AMAZING.

It’s made in one bowl, and baked in one pan (no need to layer!). You’d never guess that it’s healthier, gluten free, and made with zucchini! I’m telling you, this healthy lemon blueberry cake is next level.

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Lemon blueberry zucchini cake ingredients

This delicious gluten free blueberry zucchini cake is made with fresh, healthy produce like zucchini, lemons and blueberries, and is gluten free thanks to almond & oat flour. Just wait until you try that lemon buttercream. YUM. It’s easily dairy free, too! Here’s everything you’ll need:

• Zucchini: shredded zucchini adds the perfect amount of moisture to this cake so that we don’t have to use any oil. Be sure to measure the shredded zucchini, then squeeze it of excess moisture.
• Eggs: you’ll need two eggs in this cake recipe.
• Honey: this healthy blueberry zucchini cake is naturally sweetened with honey! You could also use pure maple syrup if you prefer but I love the honey + lemon combo.
• Lemon: we’re using both lemon juice and lemon zest for the ultimate lemon flavor.
• Almond extract: for that delicious lemon cake flavor.
• Almond flour: to keep this cake gluten free we’re using fine, blanched almond flour.
• Gluten free oat flour: we’re also mixing the almond flour with gluten free oat flour. It’s one of my favorite combos! See below for how to easily make it yourself!
• Baking soda & salt: to bake this cake up properly.
• Blueberries: pile in fresh, juicy blueberries. Yes, please!
• For the frosting: the lemon buttercream is made up of butter (or vegan butter), powdered sugar, lemon juice & lemon zest.

Can I use a different flour?

Unfortunately, I cannot recommend a substitute for the almond flour in this healthy blueberry zucchini cake as it’s the only “fat” in this recipe that helps keep the cake moist and retain its texture. For the oat flour, I think regular flour or a gluten free 1:1 flour would work well, but please note that I haven’t tested it myself.

How to make homemade oat flour

You can easily make your own gluten free oat flour by simply placing gluten free oats into a blender and blending or pulsing until they’re smooth and resemble flour. This is a super easy & affordable option. Be sure to measure out 1 cup of your oat flour after making it! It’s also important to make sure your oat flour is VERY fine. Check out my tutorial with all of my best tips & tricks.

If you want to keep this cake gluten free, I suggest using gluten free oats to make your oat flour.

Tips for making the best gluten free blueberry zucchini cake

• Squeeze out ALL of the extra moisture from your zucchini. This will ensure that the zucchini cake bakes up well and isn’t too moist. First measure the zucchini, then squeeze it of excess moisture before adding it to the batter.
• Zest your lemons before juicing them. This makes it much easier to get all of the zest from the rind!
• Toss your blueberries in a bit of oat flour before mixing them into the batter. This will ensure that the cake doesn’t turn completely blue and that the blueberries don’t fall to the bottom.
• Make this zucchini cake dairy free. Simply use a vegan buttery stick in the frosting (or swap for your favorite dairy free frosting & add a little lemon zest + lemon juice — we love Simple Mills frosting!)

How to store lemon blueberry zucchini cake

This gluten free lemon blueberry zucchini cake can actually be made 1-2 days ahead of time! You can also store it after you’ve frosted the cake, too.

• To store: feel free to keep the cake at room temp for one day. After that, I recommend storing the cake covered in the refrigerator for up to 5 days.
• To freeze: feel free to freeze this cake either frosted or unfrosted for up to 2 months. I recommend freezing it unfrosted for best results. Wrap the cake in plastic wrap, then aluminum foil and then placing the cake in a zip-top freezer bag. When you’re ready to serve it, simply thaw it in the refrigerator overnight, let the cake come to room temperature, frost it and serve it.

Tools you’ll need

Check out all of our favorite kitchen essentials here.

More zucchini recipes you’ll love

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I hope you love this easy lemon blueberry zucchini cake recipe! If you make it be sure to leave a comment and a rating so I know how you liked it. Stay tuned for more zucchini recipes all week, xo!

Lemon Blueberry Zucchini Cake with Lemon Frosting

4.97 from 99 votes

Prep Time 20 minutes

Cook Time 30 minutes

Total Time 50 minutes

Gorgeous lemon blueberry zucchini cake bursting with juicy blueberries and topped with a luscious lemon buttercream frosting. This easy, gluten free blueberry zucchini cake is made with a mix of oat and almond flour and naturally sweetened with honey. A delicious snacking cake perfect for using summer produce!

Ingredients

• Wet ingredients:
• 1 cup shredded zucchini (from 1 medium zucchini)
• 2 eggs
• ½ cup honey
• zest from 2 lemons
• 2 tablespoons fresh lemon juice
• 1/2 teaspoon almond extract
• Dry ingredients:
• 1 ½ cup packed blanched fine almond flour
• ¾ cup gluten free oat flour
• 1 teaspoon baking soda
• 1/4 teaspoon salt
• For the blueberries:
• 1 heaping cup fresh blueberries
• 2 tablespoons gluten free oat flour
• For the lemon frosting:
• ½ cup butter (or sub vegan buttery stick), at room temperature
• 1 cup powdered sugar
• 1 tablespoon fresh lemon juice
• 1 teaspoon lemon zest
• To garnish:
• Extra blueberries for sprinkling on top

Instructions

1. Preheat the oven to 350 degrees F. Line an 8×8 inch square pan with parchment paper and spray with nonstick cooking spray. Set aside.

2. First, measure out 1 cup of shredded zucchini, then place shredded zucchini in a paper towel or cheese cloth and squeeze out all of the moisture/water. This is very important!

3. Add shredded zucchini, eggs, honey, lemon zest, lemon juice and almond extract to a large bowl and whisk together until well combined.

4. Next, add dry ingredients: almond flour, oat flour, baking soda and salt. Mix together with a wooden spoon until well combined.

5. In a separate medium bowl, toss blueberries together with 2 tablespoons of oat flour. (This is to prevent the blueberries from sinking to the bottom of the cake while baking.) Fold coated blueberries into the batter.

6. Pour batter into the prepared pan. Bake for 30-35 minutes or until a tester comes out clean. Allow the cake to cool completely on a wire rack before frosting. I know this is difficult but it’s critical (otherwise the frosting will melt and become a gooey mess!)

7. Make the frosting: beat together butter, powdered sugar, lemon juice and lemon zest together on high with a hand mixer or in the bowl of an electric mixer until smooth. Spread frosting over cooled cake. Garnish with a few blueberries. Cut into 9 slices and enjoy!

Recipe Notes

I do not recommend a substitution for almond flour, as that’s the only ‘fat’ in this recipe and helps to keep the cake moist and retain its texture.

If you’re looking for an oat flour sub, I think regular flour or GF 1:1 flour would work well, but haven’t tested it myself.

Cake can be made a day ahead of time. After a day, the cake should be transferred and stored in the fridge.

Nutrition

Servings: 9 servings

Serving size: 1 slice (with frosting)

Calories: 376kcal

Fat: 21.3g

Saturated fat: 7.3g

Carbohydrates: 44.6g

Fiber: 3.6g

Sugar: 30.1g

Protein: 6.9g

Recipe by: Monique Volz // Ambitious Kitchen | Photography by: Eat Love Eats

This post was originally published on August 4, 2020,  republished on June 4, 2021, and republished on May 24th, 2023.