This zucchini coffee cake is dense, moist and perfectly flavored with cinnamon, brown sugar and vanilla. The grated zucchini melts into the batter as it bakes, leaving a tender crumb that pairs beautifully with a crunchy cinnamon streusel. Serve it for brunch, afternoon tea, or as a cozy dessert. 
Zucchini makes baked goods especially tender and moist. I love coffee cake, so making a zucchini version was a natural step. This cake is pleasantly dense but still moist, with warm notes of cinnamon, brown sugar and vanilla. Because the zucchini is grated finely, it dissolves into the batter during baking and keeps the cake soft. A buttery cinnamon streusel adds a satisfying crunch on top. An optional glaze brightens the presentation, but the cake is delicious on its own. Compared with a frosted zucchini cake, this coffee cake is slightly less sweet and more rustic in texture.
Making Zucchini Coffee Cake
Below are the key steps, tips and reasons behind the techniques used.
Start with the streusel. Combine flour, granulated sugar, brown sugar, cinnamon and salt, then whisk in melted butter until the mixture forms crumbly pieces. Using melted butter (rather than cold butter cut in) yields a slightly moister streusel that complements the cake well. 
The zucchini cake batter is made with melted butter, so you can whisk it by hand. The batter will be thick; mix gently and avoid overmixing to prevent a tough crumb.
- Whisk together the dry ingredients: flour, cinnamon, nutmeg, baking soda and salt. The warm spices boost the cake’s flavor. When measuring flour, whisk it first, spoon into the measuring cup, and level off. For accuracy, weigh ingredients on a scale.
- In a separate bowl, whisk the slightly cooled melted butter with brown sugar, granulated sugar, vanilla and eggs. Ensure the eggs are at room temperature and the butter is not hot to avoid curdling.
- Whisk the sour cream into the wet ingredients. Sour cream adds richness and keeps the cake moist and tender; it should be at room temperature for easier blending.
- Stir the finely grated zucchini into the wet mix. There’s no need to blot the zucchini; the moisture is part of the cake’s appeal.
- Make a well in the dry ingredients and pour the wet mixture into it.
- Fold the batter gently with a rubber spatula or wooden spoon until just combined. The batter will be thick—folding by hand helps prevent overmixing.
To assemble, spoon the batter into a prepared 9-inch springform pan and smooth the top. Sprinkle the streusel evenly over the batter. Bake in a preheated oven at 350°F (180°C) for about 40–45 minutes. The cake is done when a toothpick inserted into the center comes out clean or with a few dry crumbs and the center no longer wobbles. 
Pro tip: Wrap the outside of the springform pan with aluminum foil to prevent any butter from leaking if the seal isn’t perfectly tight.
Note: The streusel recipe makes a generous amount. You don’t have to use all of it—just be sure the cake is evenly covered. Some streusel will dissolve into the cake while baking, adding flavor and texture.
The glaze is optional but delightful. Wait until the cake is completely cool before drizzling the glaze so it maintains a pretty finish instead of melting into the cake.
A Note About Baking with Zucchini
Use fresh zucchini for the best texture and flavor. This recipe requires about 1 1/4 cups grated zucchini—roughly 1 medium or 1½ small zucchinis—measured after grating. There’s no need to peel the zucchini; just trim the ends and grate with a fine grater so the zucchini integrates smoothly into the batter and provides maximum moisture.
This zucchini coffee cake is moist, warmly spiced and finished with a crunchy streusel. It’s versatile—great for breakfast, brunch or as a comforting dessert. Store slices covered or in an airtight container at room temperature for up to four days; it is best enjoyed fresh.
Ingredients (summary)
Streusel: all-purpose flour, cinnamon, nutmeg, salt, granulated sugar, brown sugar, melted unsalted butter.
Cake batter: all-purpose flour, cinnamon, nutmeg, baking soda, salt, melted unsalted butter, granulated sugar, brown sugar, eggs, vanilla extract, sour cream, finely grated zucchini.
Glaze (optional): powdered sugar, milk or cream, vanilla extract.
Equipment
9-inch (23 cm) springform pan. A pan with taller sides is recommended because this recipe fills a standard 9-inch springform; an 8-inch pan will be too small.
Basic Instructions (summary)
- Preheat oven to 350°F (180°C). Grease and flour a 9-inch springform pan and wrap the outside with foil if desired.
- Make streusel: whisk dry ingredients, then stir in melted butter until crumbly; set aside.
- Whisk dry cake ingredients in one bowl. In another bowl, whisk melted butter with sugars, eggs and vanilla; add sour cream, then grated zucchini.
- Combine wet and dry ingredients by making a well in the dry mix and folding gently until just combined.
- Spoon batter into the pan, smooth the top and evenly sprinkle on streusel. Bake 40–45 minutes until a toothpick comes out clean.
- Cool completely before glazing. To glaze, whisk powdered sugar with milk and vanilla to a thin, drizzleable consistency and decorate as desired.
Notes
- Pan sizes: Use a 9-inch (23 cm) springform pan or a 9×9 inch square pan (start checking around 35 minutes for the square pan).
- Sour cream: Full-fat plain Greek yogurt can substitute for sour cream.
- Room temperature ingredients: Let eggs and sour cream come to room temperature for easier mixing.
- Zucchini: Grate finely and measure after grating; no peeling needed.
- Storage: Keep covered at room temperature up to 4 days; best fresh.
