Lemon Zucchini Cake in a 9×9 Pan
Looking for an easy, crowd-pleasing dessert that’s bursting with bright lemon flavor? This lemon zucchini cake baked in a 9×9 pan is your answer! With a tender, moist crumb from zucchini (or yellow summer squash, as I discovered!), a subtle citrus note from lemon zest and emulsion, and a vibrant lemon buttercream frosting, this cake strikes the perfect balance of tangy and sweet. It’s simple to make, requires no fancy decorating, and yields a manageable size for small gatherings. Whether you’re a baking novice or a seasoned pro, this lemon zucchini cake will become a go-to favorite!
Why You’ll Love This Lemon Zucchini Cake
This lemon zucchini cake is a standout for its ease and flavor. The zucchini or yellow summer squash keeps the cake incredibly moist without a vegetal taste, while lemon zest and a touch of lemon emulsion in the batter add a delicate citrus glow. The real star is the lemon buttercream frosting, which delivers a bold, tangy punch that’s just right—not too overpowering. Using all butter in the batter (or an optional butter-avocado oil blend for a lighter texture) creates a rich yet tender crumb. I recently made this with yellow summer squash from my garden, and the buttercream elevated the gentle lemon flavor into something truly special. Baked in a 9×9 pan, it’s the perfect size for 9–12 servings, making it ideal for cozy gatherings or a family dessert.
Tips for the Perfect Lemon Zucchini Cake
- Zucchini or Squash: Zucchini and yellow summer squash are interchangeable in this lemon zucchini cake, both adding moisture and a tender texture. Don’t squeeze out the liquid, but if the squash is very watery, lightly pat with a paper towel.
- Avocado Oil Option: Using ¼ cup (56 g) avocado oil in place of ¼ cup butter creates a lighter, slightly less dense cake while maintaining moisture. Choose a neutral-tasting avocado oil and measure accurately for best results.
- Lemon Emulsion: The 1 teaspoon of lemon emulsion enhances the cake’s subtle citrus flavor without overpowering it. For a bolder lemon note, try 1 ½ teaspoons, but taste-test to keep it balanced.
- Frosting for a 9×9 Pan: This smaller batch of buttercream (about 1 cup) is perfect for a 9×9 pan, providing a thin to medium layer. For a thicker layer, increase by 25% (e.g., 141 g butter, 300 g powdered sugar).
- Storage: Store the frosted lemon zucchini cake in an airtight container at room temperature for up to 2 days or in the fridge for up to 5 days. Bring to room temperature before serving. Unfrosted cake can be frozen for up to 3 months; thaw before frosting.
Why Bake in a 9×9 Pan?
Baking this lemon zucchini cake in a 9×9 pan is a user-friendly choice for home bakers. The manageable size yields 9–12 servings, perfect for small gatherings or family desserts without overwhelming leftovers. Unlike layered cakes, this single-layer cake requires no complicated decorating—just spread on the lemon buttercream and you’re done! The 9×9 pan creates a thicker, tender cake that’s easy to slice into neat squares, making it ideal for fuss-free preparation and serving. If using an 8×8-inch pan, increase baking time by 3–5 minutes and check for doneness.
Final Thoughts
This lemon zucchini cake in a 9×9 pan is a delightful blend of moist, tender cake and vibrant lemon buttercream. The all-butter batter (or optional butter-avocado oil blend for a lighter texture) pairs beautifully with the subtle citrus flavor from lemon emulsion and zest, while the frosting adds a bold, tangy finish. Whether you use zucchini or yellow summer squash, this easy recipe delivers a perfectly balanced dessert every time. It’s ideal for summer gatherings, cozy afternoons, or anytime you want a bright, and easy summer treat.
Have you tried this lemon zucchini cake? Share your thoughts or any creative twists (like yellow squash or the avocado oil option!) in the comments below. For more baking inspiration, check out my other dessert recipes or share this one with other dessert lovers!
Lemon Zucchini Cake
Print Recipe
EQUIPMENT (affiliate links)
- 9×9-inch square baking pan
- Box grater (or food processor)
- Electric mixer (stand or handheld)
Ingredients
For the Lemon Zucchini Cake
- 1 ¾ cups unbleached all-purpose flour, spooned & leveled 210g
- 1 tsp baking powder
- ½ tsp baking soda
- ½ tsp salt
- 1 cup 200 g granulated sugar 200g
- ¾ cup salted butter, melted and cooled (see note for a lighter cake) 170g
- 2 large eggs
- 2 tbsp lemon zest (from 2 medium lemons)
- ¼ cup fresh lemon juice 60g
- 1 tsp vanilla extract
- 1 tsp lemon emulsion
- 1 ½ cups grated zucchini or yellow summer squash, lightly packed (from 1 medium zucchini or squash, un-squeezed) 180g
For the Lemon Buttercream Frosting
- ½ cup salted butter, softened to room temperature 113g
- 2 cups powdered sugar, sifted 240g
- 1 ½ tsp fresh lemon juice 22g
- 2 tsp lemon zest (from 1 small lemon)
- ¼ tsp vanilla extract
- 1-2 tsp heavy cream or milk (optional, for consistency)
- ⅛ tsp salt
Instructions
- Preheat and Prep: Preheat oven to 350°F (175°C). Grease a 9×9-inch square baking pan.
- Grate the Zucchini or Squash: Grate 1 medium zucchini or yellow summer squash to yield 1 ½ cups (180 g) lightly packed. Don’t squeeze out moisture—it keeps the cake tender. Set aside.
- Mix Dry Ingredients: In a medium bowl, whisk flour, baking powder, baking soda, and salt until combined.
- Combine Wet Ingredients: In a large bowl, whisk granulated sugar and ¾ cup (170 g) melted butter until smooth. For a lighter cake, use ¼ cup (56 g) avocado oil and ½ cup (113 g) butter). Add eggs, lemon zest, lemon juice, vanilla extract, and lemon emulsion, whisking until smooth.
- Make the Batter: Add dry ingredients to wet ingredients in two additions, stirring gently with a spatula until just combined. Avoid overmixing.
- Add Zucchini or Squash: Fold in grated zucchini or yellow summer squash until evenly distributed.
- Bake: Pour batter into the prepared 9×9 pan and smooth the top. Bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs. If using avocado oil, check at 30 minutes. Cool in pan completely.
- Prepare Lemon Buttercream: Beat softened butter with an electric mixer on medium speed until creamy, about 1 minute. Gradually add sifted powdered sugar, lemon juice, lemon zest, vanilla extract, and salt. Beat for 1–2 minutes until fluffy. Add heavy cream or milk, 1 teaspoon at a time, if needed for spreadable consistency.
- Frost and Serve: Spread lemon buttercream evenly over the cooled cake, creating a ¼-inch layer. Garnish with extra lemon zest or lemon slices, if desired. Cut into 9 or 12 squares and serve at room temperature.
Notes
- Zucchini or Squash: Zucchini and yellow summer squash both work beautifully in this lemon zucchini cake, adding moisture and tenderness. Don’t squeeze out liquid; if very watery, lightly pat with a paper towel.
- Avocado Oil Option: For a lighter texture, use ¼ cup (56 g) avocado oil in place of ¼ cup butter. It adds moisture and a neutral flavor, complementing the butter’s richness.
- Lemon Emulsion: The 1 tsp lemon emulsion enhances the cake’s subtle citrus flavor. For a stronger note, try 1 ½ tsp, but taste-test to avoid overpowering.
- Why a 9×9 Pan?: The 9×9 pan is user-friendly, requiring no complicated decorating—just spread on the frosting! It yields a manageable size (9–12 servings), perfect for small gatherings without excess leftovers. If using an 8×8-inch pan, increase baking time by 3–5 minutes.
- Storage: Store frosted cake in an airtight container at room temperature for up to 2 days or in the fridge for up to 5 days. Bring to room temperature before serving. Unfrosted cake can be frozen for 3 months; thaw before frosting.
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