Sourdough Blueberry Crumb Cake

My family has shopped at Costco since I was a child. I was actually brought home from the hospital to Kirkland, Washington (Costco’s headquarters city) where my parents lived at the time. That name may sound familiar to you if you’ve shopped at Costco, because Kirkland is the “Costco” store brand. My grandma used to buy us Costco muffins (you know those giant muffins that are more like cake than muffin?!) and I would always, always pick blueberry. I love the taste of the tart blueberries mixed with a sweet muffin. The minute I cut into this sourdough blueberry crumb cake I had a childhood flashback to those Costco muffins. This cake is thick and full of blueberries. It also has considerably less sugar than a Costco muffin and is jam-packed with tart blueberries. The crumb topping takes it over the top and had me coming back for “tastes” throughout the day. If you are also a fan of blueberry muffins, you’ve got to try this sourdough blueberry crumb cake.

Jump to Sourdough Blueberry Crumb Cake Recipe

Sourdough Discard or Sourdough Starter?

If you’re new around here, you may not know that I love baking with sourdough. I’ve got a whole bunch of recipes that use sourdough discard and sourdough starter. Because I refresh my sourdough starter often, I end up with quite a bit of leftover discard in my fridge. I don’t like this discard to go to waste, so I find muffins, waffles, crackers, pretzels and breads to put it into. The sourdough discard enhances the flavor and creates less kitchen waste. Not all sourdough discard is created equal, though. The longer the discard sits in your fridge, the more fermented and sour it will taste. If you like this flavor in your baked goods, use discard that is older. For a more mellow flavor, use discard that is only a day or two old. If you love baking with sourdough but don’t want any sour flavor, use bubbly sourdough starter instead of the discard.

Fresh or Frozen Blueberries?

My local Kroger had a great deal on blueberries this past week, so I used fresh blueberries in this sourdough blueberry crumb cake. The fresh blueberries gave this crumb cake delicious flavor. If you can, I recommend using fresh blueberries. If fresh isn’t not an option, you can use frozen blueberries. Truthfully I don’t always have fresh blueberries on hand and more often than not have a bag of frozen berries available. Toss the frozen blueberries in 1-2 teaspoons of flour, lightly coating them before stirring the berries into the cake mixture. This helps so they don’t all fall to the bottom of the cake and will be more evenly dispersed throughout. I’ve made this sourdough blueberry crumb cake with fresh and frozen blueberries and it’s delicious both times. The frozen blueberry cake did take a little more time to bake, so be prepared to add on 5-10 minutes of bake time if you use frozen blueberries.

Blueberry Crumb Topping

One of the things that sets this cake apart is the delicious crumb topping. Melt the butter, add in the dry ingredients and mix together with a spoon until you get a thick and crumbly topping. Use your fingers to sprinkle the crumb topping all over the top of the cake. I also like to dot the top of the cake with a few more fresh blueberries, pressing them in between pieces of crumb topping so that there is blueberry in every bite. Once this crumb topping is baked up, it makes the perfect sweet, crumbly crust. My four year old could be found sneaking pieces of crumb topping all. day. long. And I don’t blame him. It is GOOD!

Baking the Sourdough Blueberry Crumb Cake

Sourdough blueberry crumb cake takes a little over an hour to bake. It bakes up nice and tall and can be cut into 16 good sized pieces. Preheat the oven to 350 degrees and bake the crumb cake for a little over an hour. I like to check on the cake after about 55 minutes (oven temperatures can vary). If the cake is jiggly in the middle, keep baking for another 10 minutes. I’ve found that my cake needs about 65-75 minutes to bake all the way through. If you are using frozen blueberries it may take a little bit longer than if using fresh blueberries.

I love this sourdough blueberry crumb cake. It is not overly sweet (you can add a little more sugar if you want a sweeter cake) and the blueberry really shines through. The cake rises beautifully and would be perfect for a family brunch, to pull out as a special after-school snack or even to drink with a cup of tea on a snowy day. If you are a blueberry muffin lover like me, add this recipe to your “to-make” list. It’s delicious.

Sourdough Blueberry Crumb Cake

Sourdough blueberry crumb cake is a lightly sweetened cake made with sourdough discard, studded with sweet blueberries and topped with a sweet crumb topping. Perfect for breakfast, brunch or a snack, this crumb cake is delicious!
Prep Time 20 mins
Cook Time 1 hr 5 mins
Course Breakfast, Dessert, Snack
Cuisine American
Servings 16 slices

Ingredients
  

Crumb Topping

  • 6 Tablespoons unsalted butter melted
  • 1/3 cup granulated sugar
  • 1 teaspoon vanilla extract
  • 1 teaspoon cornstarch
  • 1/2 teaspoon salt
  • 1 cup all purpose flour

Sourdough Blueberry Cake

  • 1.5 cups all purpose flour
  • 1 Tablespoon cornstarch
  • 1/2 teaspoon baking soda
  • 1 teaspoon baking powder
  • 1/2 teaspoon salt
  • 6 Tablespoons unsalted butter softened
  • 2/3 cup granulated sugar
  • 1 egg
  • 1 egg yolk
  • 2 teaspoons vanilla extract
  • 3/4 cup sourdough discard or bubbly sourdough starter
  • 1/2 cup buttermilk see recipe notes for substitutions
  • 2.5 cups fresh blueberries see recipe note for frozen blueberries

Instructions
 

Crumb Topping

  • Melt 6 Tablespoons of butter. Add the sugar, vanilla, cornstarch, salt and flour. Mix together until it forms a moist, crumbly topping. Set aside the crumb topping for later.

Sourdough Blueberry Cake

  • Preheat oven to 350 degrees.
  • To a small bowl, add the flour, cornstarch, baking soda, salt and baking powder. Fluff together with a fork. Set aside.
  • Using a stand mixer or a handheld mixer, mix together the softened butter and granulated sugar until light and creamy.
  • Add the egg, egg yolk and vanilla. Mix again, scraping the sides and bottom as needed until fully incorporated, light and fluffy.
  • Pour ¾ cup sourdough discard (direct from the fridge or use ripe sourdough starter) and add to the bowl. Mix together.
  • Add the flour mixture and mix until just incorporated. Pour in the buttermilk and mix until smooth.
  • Add 2 cups of fresh blueberries (reserving ½ cup for topping) to the batter and stir lightly to combine. See recipe note if using fresh blueberries.
  • Line an 8 by 8 pan (my favorite, affiliate link) with parchment paper. Pour blueberry cake mixture into the pan and spread evenly.
  • Sprinkle the crumb mixture on top of the cake, spreading it evenly and breaking up clumps with your fingers as you go. Dot the top with the reserved ½ cup of blueberries.
  • Bake the cake for 60-75 minutes until baked through. Once the cake has stopped jiggling in the middle, take a sharp knife and stick it straight in the middle of the cake. If it has batter on it, continue baking a few more minutes. If it comes out clean, the cake is finished baking.
  • Cool and slice to serve. The cake stores well at room temperature for a day or two or can be frozen for longer storage.

Notes

Buttermilk: If you don’t have buttermilk on hand, you can substitute 1/4 cup milk mixed with 1/4 cup sour cream.
Blueberries: Fresh blueberries are best for this recipe, but frozen blueberries work too in a pinch. If using frozen blueberries, toss them in 1-2 teaspoons of flour and then gently stir into the batter. This helps the blueberries spread throughout the cake and not sink to the bottom. Using frozen blueberries may also increase the baking time about 10 minutes. 
Keyword blueberry, crumb cake, snack cake

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Amy

Only posting the best recipes to make you a rockstar in the kitchen.

One thought on “Sourdough Blueberry Crumb Cake

  1. What a beautiful blueberry bake!! I love your early Costco muffin memories…so true! Thanks for sharing this amazing recipe, as well as your tips for baking with fresh vs. frozen berries! 🙌🏻🫐😋

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