Description
Bright blueberries meet sneaky shredded zucchini in this easy sheet cake, finished with a tangy lemon buttercream. It’s a great summer bake that holds up well chilled — perfect for potlucks or a weekday treat.
Ingredients
Scale
Cake
- 3 large eggs
- 1 cup vegetable oil
- 1 tablespoon vanilla extract
- 2 1/4 cups granulated sugar
- 2 cups finely grated zucchini
- 3 cups all-purpose flour
- 1 teaspoon salt
- 1 teaspoon baking powder
- 1/4 teaspoon baking soda
- 1 pint fresh blueberries, lightly tossed with 1 teaspoon flour
Lemon Buttercream
- 3/4 cup unsalted butter (1½ sticks), softened to room temp
- 4 cups powdered (confectioners’) sugar, sifted
- Fresh lemon juice (start with a couple tablespoons; adjust to taste)
Instructions
- Preheat your oven to 350°F (175°C). Grease a 9×13-inch pan and dust it lightly with flour or line it with parchment for easy removal.
- In a large bowl, whisk together the eggs, oil, vanilla, and granulated sugar until smooth and well combined. Gently fold the grated zucchini into this mixture.
- In a separate bowl, combine the flour, salt, baking powder, and baking soda — whisk to blend the dry ingredients evenly.
- Add the dry mixture to the wet ingredients in two additions, stirring just until the batter is uniform. Don’t overwork it; a few small streaks of flour are fine.
- Carefully fold the floured blueberries into the batter so they distribute without bursting.
- Spread the batter into the prepared 9×13 pan and smooth the top. Bake for about 50 minutes, or until the surface turns light golden and a toothpick inserted into the center comes out clean or with only a few moist crumbs attached.
- Remove from the oven and let the cake cool on a rack until it reaches room temperature before frosting.
Lemon Buttercream (Make It Smooth)
- Put the softened butter into the bowl of a food processor (or use a stand mixer). Process or beat until it becomes pale and creamy.
- Add the powdered sugar a cup at a time, processing briefly after each addition until incorporated. After about two cups of sugar, pour in a splash of fresh lemon juice and continue adding sugar and juice alternately until you reach a spreadable consistency and your desired lemon brightness.
- Scrape the sides as needed to ensure everything blends evenly. If the frosting is too stiff, add a little more lemon juice (or a teaspoon of milk). If it’s too loose, add a bit more powdered sugar.
- Once the cake is fully cool, spread the lemon buttercream evenly over the top. Chill in the refrigerator to set if you prefer a firmer, cooler texture.
Notes
- Notes & Tips
- Gluten-free option: Readers have successfully swapped in a 1:1 gluten-free measure-for-measure flour blend (for example, King Arthur Measure for Measure) with great results.
- Serve chilled: This cake shines when kept cool — the lemon buttercream firms up really nicely in the fridge, and the chilled slices have an especially pleasant texture.
- Make-ahead & storage: Keep the frosted cake refrigerated for up to 4 days. You can also freeze single slices wrapped tightly and thaw in the fridge overnight.
- Blueberry handling: Tossing the berries in a little flour before folding them into the batter helps prevent sinking and color bleeding.
- For chocolate lovers: If you want a different chilled treat, try the Cold Chocolate Snacking Cake on my site — it’s designed to be enjoyed straight from the refrigerator and is seriously irresistible.
Nutrition
- Calories: 462 kcal
- Sugar: 61 g
- Sodium: 177 mg
- Fat: 15 g
- Saturated Fat: 11 g
- Carbohydrates: 81 g
- Fiber: 2 g
- Protein: 4 g
- Cholesterol: 31 mg