Moist Zucchini Coffee Cake with Brown Sugar Streusel
This zucchini coffee cake is our go-to when summer squash piles up faster than we can grill it. The cake bakes up tender and spicy, crowned with a thick brown sugar crumble.
It’s a simple stir-together batter with no mixer required, and nobody will guess there’s a vegetable hiding in there.
Why This Cake Stays on the Counter All Week
The crumb is what does it for me. Finely grated zucchini melts into the batter, leaving behind a cake so damp and soft you can skip the morning coffee and just eat this.
That streusel gets shatteringly crisp on top yet stays a little sandy underneath. Between the warm cinnamon and the deep sweetness, it makes the whole house smell like a bakery.
It keeps for days, gets better overnight, and manages to feel like a treat without being overly sweet.
Ingredients
- 1 1/2 cups (190g) all-purpose flour: spooned and leveled so it doesn’t turn out heavy.
- 1 tsp baking powder
- 1/2 tsp baking soda
- 1/2 tsp fine sea salt
- 1 1/2 tsp ground cinnamon
- 1/4 tsp ground nutmeg
- 2 large eggs, at room temperature
- 3/4 cup (150g) granulated sugar
- 1/3 cup (80ml) vegetable oil or melted coconut oil: any neutral oil works.
- 1/4 cup (60g) sour cream or plain yogurt: adds tang and tenderness.
- 1 tsp vanilla extract
- 1 1/2 cups (180g) finely grated zucchini: squeeze out excess moisture if it’s very wet, but don’t wring it dry.
- For the streusel:
- 2/3 cup (85g) all-purpose flour
- 1/2 cup (100g) packed light brown sugar
- 1 tsp ground cinnamon
- 1/4 cup (57g) unsalted butter, cold, cut into cubes
Variations / Substitutions
- Gluten-free: Use a cup-for-cup GF flour blend.
- Dairy-free: Use coconut oil and your favorite vegan sour cream or yogurt, plus a plant-based butter for the streusel.
- Spice it up: Add 1/2 tsp cardamom and a pinch of cloves for a chai vibe.
- Chocolate chips: Fold in 1/2 cup mini chocolate chips for a dessert-like twist.
If you’re on a zucchini roll, our Chocolate Zucchini Bread is another great way to bake through a bumper crop.
How to Make Moist Zucchini Coffee Cake
Step 1: Whisk the Dry Ingredients
Preheat the oven to 350°F (175°C) and line an 8×8 or 9×9 inch baking pan with parchment. In a medium bowl, whisk together the 1 1/2 cups flour, 1 tsp baking powder, 1/2 tsp baking soda, 1/2 tsp salt, 1 1/2 tsp cinnamon, and 1/4 tsp nutmeg until no lumps remain.
The mixture should smell fragrant and look evenly speckled. This step means you won’t overmix later trying to distribute the leaveners.
Step 2: Blend the Wet Ingredients
In a large bowl, whisk the 2 eggs and 3/4 cup sugar until pale and slightly thickened, about 1 minute. Whisk in the 1/3 cup oil, 1/4 cup sour cream, and 1 tsp vanilla until smooth.
The batter base will be glossy and thick. Don’t skip whisking the eggs and sugar together first; it helps the cake rise evenly.
Step 3: Fold in the Zucchini
Pour the dry ingredients into the wet mixture and stir with a spatula just until no dry streaks remain. Fold in the 1 1/2 cups grated zucchini, making sure it’s evenly distributed but not beaten to a pulp.
The batter will look very wet and slightly green flecked. At this point, it’s ready for the pan, so don’t let it sit or the baking powder will start losing its punch.
Step 4: Make the Streusel
In a small bowl, combine the 2/3 cup flour for the streusel, 1/2 cup brown sugar, and 1 tsp cinnamon. Add the 1/4 cup cold butter cubes and rub them in with your fingertips until the mixture clumps together in pea-sized crumbs.
The streusel should feel like wet sand and hold its shape when squeezed. If your kitchen is warm, pop the bowl in the fridge for 5 minutes so the butter stays cold.
Step 5: Layer and Bake
Scrape the batter into the prepared pan and smooth the top. Sprinkle the streusel evenly over the batter, pressing very lightly so it sticks. Bake on the center rack for 50 to 55 minutes, until a toothpick inserted in the center comes out with just a few moist crumbs.
The top will be deeply golden and the whole kitchen will smell like cinnamon. If the streusel threatens to brown too quickly, tent with foil after 40 minutes.
Step 6: Cool and Slice
Set the pan on a wire rack and let the cake cool completely in the pan, about 1 hour. Lift it out by the parchment, then slice into squares and serve.
The cake is delicate when warm, so patience pays off. Once cool, the slices hold a perfect crumb and that streusel gets satisfyingly crunchy.
A Few Notes for a Flawless Cake
- Zucchini size: Small to medium zucchini are best. Large ones have bigger seeds and more water, which can make the cake heavy.
- Grating: A food processor with the shredding disc makes quick work, but a box grater works too. No need to peel unless the skin is tough.
- Cooling: If you try to slice it while it’s still warm, the cake will crumble. Let it cool completely in the pan for clean squares.
Bake times vary slightly by pan:
| Pan Size | Material | Bake Time |
|---|---|---|
| 8×8 or 9×9 inch | Metal | 50 to 55 mins |
| 8×8 inch | Glass | 55 to 60 mins |
| Loaf pan | Metal | 60 to 65 mins |
Keeping the Cake Fresh
- Refrigerate: Store covered at room temperature for up to 3 days, or in the fridge for up to a week. The cake actually gets moister overnight.
- Reheating: A quick 15 second zap in the microwave brings back that just-baked softness.
- Serve Cold: It’s also delicious straight from the fridge, especially with a tall glass of iced coffee.
What to Serve Alongside This Cake
A hot cup of dark roast coffee cuts through the sweetness of the streusel nicely. For a brunch spread, it’s great with a side of plain Greek yogurt and fresh berries to balance the richness.
Frequently Asked Questions
Can I freeze zucchini coffee cake?
Yes. Wrap the cooled cake tightly in plastic wrap, then foil, and freeze for up to 3 months. Thaw overnight at room temperature.
Can I use butter instead of oil?
You can, but the cake will be slightly less moist. Use 6 tablespoons melted unsalted butter in place of the oil.
Can I omit the streusel?
Of course. You will lose that crunchy contrast, but the cake is still tender and great on its own.
Do I need to peel the zucchini?
No, the skin is thin and tender, and the green flecks look pretty. Peel it only if the skin feels tough.
Zucchini Coffee Cake Recipe
Ingredients
Method
- Preheat oven to 350°F (175°C). Line an 8×8 or 9×9 inch baking pan with parchment. In a medium bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, and nutmeg.
- In a large bowl, whisk the eggs and granulated sugar until pale and slightly thickened, about 1 minute. Whisk in the oil, sour cream, and vanilla until smooth.
- Pour the dry ingredients into the wet mixture and stir until just combined. Fold in the grated zucchini until evenly distributed.
- In a small bowl, combine the streusel flour, brown sugar, and cinnamon. Cut in the cold butter with your fingertips until the mixture forms pea-sized crumbs.
- Scrape the batter into the prepared pan and smooth the top. Sprinkle the streusel evenly over the batter, pressing lightly. Bake for 50 to 55 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
- Cool the cake completely in the pan on a wire rack, about 1 hour. Lift out using the parchment, slice, and serve.
