This sourdough blueberry crumb cake is everything I love about weekend baking—easy, cozy, and full of flavor. It started with a jar of discard I couldn’t bear to waste and a pint of blueberries that needed a home. The result?

A golden, tender cake with sweet bursts of berries and a buttery crumble that’s impossible to resist. It’s one of those bakes that feels like a hug on a plate—perfect for brunch, snacking, or that quiet afternoon coffee break you’ve been craving.

What Makes This Sourdough Blueberry Crumb Cake Delight So Special

What sets this sourdough blueberry crumb cake apart isn’t just the dreamy combination of sweet fruit and buttery topping—it’s the smart use of sourdough discard that transforms it into something extra special. With its light tang and soft, moist crumb, this cake is a simple joy to make and even better to eat.

The Secret is in the Sourdough

Using sourdough discard gives this cake more than just a tangy twist—it adds depth and keeps the texture wonderfully soft. It’s a clever way to reduce food waste and boost flavor all at once. The starter works with the baking soda and sour cream to create a tender, airy crumb that stays moist for days.

Sourdough discard isn’t just for bread—it gives baked goods a complex flavor you can’t get any other way.

Even if you’re new to baking with discard, this recipe is forgiving and beginner-friendly. No long fermentation, no fuss—just mix and bake.

Why the Crumble & Blueberries Shine

That buttery, cinnamon-scented crumble layered over and under the blueberries makes each bite feel like a little celebration. The crumble toasts up beautifully in the oven, while the juicy berries add freshness and a pop of sweet-tart flavor.

The secret to an even bake?

Dust the blueberries in a bit of powdered sugar to keep them from sinking. This ensures every square of cake has just the right balance of soft crumb, fruit, and crunch.

Whether you’re baking for guests, gifting a treat, or just making something cozy for yourself, this cake fits the moment beautifully.

Ingredients & Why They Matter

One of the things I love most about this sourdough blueberry crumb cake is how it makes the most of everyday ingredients. Each element plays a role in creating a cake that’s rich, moist, and full of texture.

Star Ingredients & Their Roles

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  • Sourdough discard: This is your secret ingredient. It adds a subtle tang that balances the sweetness and brings a tender crumb to the cake. A 100% hydration starter works best here.
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  • Blueberries: Use fresh if you can. Tossing them with powdered sugar helps prevent sinking and adds a touch of sweetness.
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  • Sour cream: Adds richness and moisture without making the batter too dense. It also helps create that velvety texture.
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  • Browned butter: Infuses the cake with a warm, nutty depth you can’t get from regular melted butter. Just watch it carefully—it browns fast!
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  • Crumb topping: A mix of flour, sugar, cinnamon, and cold butter. It gives the cake that bakery-style finish, with layers of crunchy sweetness.
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  • Baking powder & soda: These leavening agents work with the sour cream and discard to help the cake rise just right.
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  • Egg & sugar: The egg gives structure; sugar brings sweetness and helps caramelize the crumb topping beautifully.

Ingredient Substitutions & Options

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  • No sour cream? Full-fat Greek yogurt works well as a substitute.
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  • Frozen blueberries? You can use them, but don’t thaw. Toss them in a bit of flour or powdered sugar to avoid streaks.
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  • Lactose-free? Use plant-based sour cream and butter substitutes.
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  • Gluten-free? A 1:1 gluten-free flour blend can be used, but expect a slightly different texture.

These thoughtful ingredient choices make this cake adaptable, foolproof, and endlessly satisfying.

How to Make Sourdough Blueberry Crumb Cake

This sourdough blueberry crumb cake comes together in layers, but the steps are easy to follow. The trick is not rushing through the prep—each piece plays a role in creating a soft, tender crumb with that signature crumble top.

Step-by-Step Directions

Step 1: Preheat and Prep the Pan
Start by preheating your oven to 350°F (176°C). Lightly grease an 8×8-inch baking pan and line it with parchment paper. Press the parchment into the corners and sides so it lays flat. This makes removing the cake super easy later.

Step 2: Prep the Blueberries
Place fresh blueberries in a small bowl and sift about 1 tablespoon of powdered sugar over them. Gently toss to coat. This helps prevent them from sinking into the cake as it bakes, giving you a perfect berry distribution throughout.

Step 3: Make the Crumb Topping
In a medium bowl, whisk together the all-purpose flour, sugar, light brown sugar, cinnamon, and a pinch of salt. Add the cold, cubed butter. Use your fingers to pinch and rub the mixture until it forms small clumps—like coarse crumbs with a few larger chunks. Place the topping in the fridge while you prep the batter.

Step 4: Brown the Butter
In a small skillet, melt 1 stick of butter over medium heat. Let it cook for a few minutes until it turns golden brown around the edges and smells nutty. Watch closely—once it starts to brown, it can burn fast. Remove from heat and let cool slightly.

Step 5: Mix the Wet Ingredients
In a large bowl or stand mixer, combine the sugar, egg, and sourdough discard. Beat on medium-low for about 1 minute. While mixing, slowly pour in the slightly cooled browned butter. This step locks in flavor and adds moisture.

Step 6: Sift and Mix the Dry Ingredients
In a separate bowl, whisk or sift the flour, baking powder, baking soda, and salt together to keep everything light and lump-free.

 Add these dry ingredients to your wet mixture and mix gently on low speed. You should still see some flour specks. Don’t overmix!

Step 7: Add the Sour Cream
Gently fold in the sour cream until the batter is thick and smooth. It might look dense at first, but that’s exactly what gives this cake its rich, velvety crumb.

Step 8: Assemble the Cake
Spoon the batter into the prepared baking pan and smooth the top with a spatula. Now it’s time to layer. Sprinkle half the crumble topping over the batter, followed by half the blueberries. Repeat with the remaining crumble and berries.

Step 9: Bake the Cake
Place the pan on the center rack and bake for 55–65 minutes. Begin checking around the 55-minute mark. Insert a toothpick or dry piece of spaghetti into the center—if it comes out clean or with a few crumbs, it’s ready.

Step 10: Cool & Serve
Let the cake cool in the pan for at least 30 minutes before slicing. This helps it set fully and makes slicing cleaner. Once cool, dust with a little more powdered sugar if you like, then cut into squares and serve.

Serving, Storage & Variations

Once cooled, this sourdough blueberry crumb cake becomes more than just a treat—it turns into a comforting little ritual. Whether you're slicing it for a casual brunch or enjoying it as an after-dinner sweet, it's a recipe that fits any time of day.

Serving Suggestions to Savor

You don’t need much to make this cake shine. A simple dusting of powdered sugar over the top gives it that bakery-style finish, while the golden crumble and juicy blueberries speak for themselves.

If you're hosting, offer it with coffee or hot tea—it’s a guaranteed hit at brunch tables or cozy afternoon catch-ups.

For a touch of indulgence, a spoonful of lightly sweetened whipped cream or a small scoop of vanilla bean ice cream brings out the richness in every bite.

Storing & Freezing Tips

The beauty of this cake is that it tastes even better the next day—moist, flavorful, and still bakery-fresh with minimal effort.

Keep leftovers in an airtight container at room temperature for up to 3 days. If you’re planning to stretch it out a bit longer, store it in the fridge for up to 5 days—just bring it back to room temperature before serving for best flavor.

Cut the cake into single servings and snugly wrap each one in plastic wrap—makes grabbing a treat later super easy! Pop the wrapped pieces into a freezer-safe bag, and they’ll stay delicious for up to two months.

Let it sit out at room temperature to thaw, or warm it slightly in the oven or microwave if you want that cozy, fresh-from-the-oven goodness.

Easy Flavor Variations

This recipe is a beautiful base to build on. Here are a few twists you can try:

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  • Swap the berries: Raspberries, blackberries, or even chopped peaches add variety.
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  • Add citrus: Stir in lemon or orange zest for a bright lift.
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  • Make it nutty: Add chopped pecans or almonds to the crumble topping for crunch.
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  • Use dairy-free subs: A good quality plant-based sour cream and butter works great if needed.

This cake invites creativity, and it always rewards you with flavor, no matter how you make it your own.

Conclusion

This sourdough blueberry crumb cake has quickly become one of those recipes I turn to again and again—especially when my sourdough jar is staring me down from the fridge.

It’s easy to pull together, endlessly comforting, and somehow feels both homey and special at the same time. The sweet crumble, the juicy berries, that tangy hint from the discard—it all just works.

I hope you give it a try and make it your own. And hey, if it becomes your go-to for brunches, bake sales, or quiet mornings with coffee, I’d love to hear about it.

Sourdough Blueberry Crumb Cake FAQs

Can I use a 9×9 pan instead of an 8×8?
Yes, you can use a 9×9-inch pan, but your cake will bake a little faster since the batter spreads out more. Start checking for doneness around the 50-minute mark and use a toothpick test.

Do I have to brown the butter?
Technically, no—but you really should! Browning the butter adds a deep, nutty flavor that makes this sourdough blueberry crumb cake extra special. Just be sure not to burn it—watch for golden edges and a toasty aroma.

Can I use frozen blueberries?
Absolutely. Just toss them in a little powdered sugar or flour straight from the freezer (no thawing!), and fold them in gently. This prevents bleeding and soggy spots.

How do I keep the crumble topping from sinking?
The trick is layering—half the crumble, half the berries, then repeat. Also, make sure your crumble mixture is cold and clumpy before adding it to the batter. It will stay on top and toast up beautifully.