Potato Flake Sourdough Blueberry Coffee Cake Recipe

This potato flake sourdough blueberry coffee cake is such a delicious treat. It can be made with discard or active starter. It is a moist, flavorful treat loaded with juicy blueberries and topped with a buttery cinnamon crumb topping.

Whether you’re looking for a delightful breakfast, a coffee-time indulgence, or a dessert to impress your family and friends, this recipe will become a staple in your home.

Why You’ll Love This Blueberry Crumb Cake

• Perfectly Moist Texture: The combination of potato flake sourdough discard, yogurt, and coconut oil creates a tender, rich crumb.
• Balanced Sweetness: The sourdough discard adds depth to the sweetness of the cake.
• Bursting with Blueberries: Every bite is loaded with juicy blueberries that complement the warm cinnamon topping.
• Easy to Make Ahead: Thanks to the bulk fermentation step, you can prepare the batter in advance for a more developed flavor.
• A Great Way to Use Potato Flake Sourdough Discard: This recipe is an excellent addition to your sourdough discard recipes collection.

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Tools You’ll Need

To make this recipe as smoothly as possible, gather these kitchen tools before you start:

• Medium bowl – To mix the crumb topping.
• Small bowl – For coating the blueberries.
• Large bowl – For mixing the batter and allowing it to ferment.
• Whisk – To combine wet ingredients smoothly.
• Rubber spatula – Helps to fold the ingredients together without over mixing.
• Measuring cups and spoons – For accurate ingredient portions.
• Plastic wrap– To cover the batter during bulk fermentation.
• 9×13-inch baking dish or loaf pans – The perfect size for this cake.
• Fork – To create a crumbly texture for the topping.
• Toothpick – For testing doneness.
• Wire rack – For cooling the cake after baking.

Ingredients You’ll Need

Bulk Ferment (Prepare 8 Hours in Advance)

• All-purpose flour
• Raw organic sugar
• Melted coconut oil or butter (cooled but not hot)
• Potato flake sourdough starter (active or discard)
• Milk (room temperature)
• Eggs (room temperature)
• Plain yogurt (or sour cream)

After Bulk Ferment

• Baking soda
• Baking powder
• Salt
• Vanilla extract

Add-ins

• 2-3 cups fresh blueberries or frozen blueberries
• 1–2 tablespoons flour (for coating blueberries)

Crumb Topping

• 1 cup all-purpose flour
• ⅔ cup sugar
• 1 stick (½ cup) salted butter, melted
• 2 teaspoons cinnamon

How to make Potato Flake Sourdough Blueberry Coffee Cake

Prepare the Bulk Ferment Batter

In a large mixing bowl, whisk together the eggs and sugar until combined.

Add the yogurt, coconut oil (or butter), and potato flake starter. Stir until smooth.

Add the all-purpose flour and mix everything together with a rubber spatula. Be sure to scrape the sides of the bowl to make sure that everything is mixed well. 

Cover the bowl with plastic wrap and let it sit at room temperature for 8 hours. This fermentation step develops the flavor and improves digestibility.

Preheat and Prepare the Baking Dish

The next morning, or after the fermentation period, preheat your oven to 350°F (175°C). You should see small bubbles forming on the top of the batter. 

Lightly grease a 9×13-inch baking dish or loaf pans with butter or nonstick spray. You can also line with parchment paper if desired. 

Make the Crumb Topping

In a medium bowl, mix together the flour, sugar, and cinnamon.

Pour the melted butter in the flour mixture and stir with a fork until the mixture forms small crumbs. Set aside.

Incorporate the Final Ingredients

Add the baking soda, baking powder, salt, and vanilla extract to the fermented batter.

Mix well until fully incorporated. If using a stand mixer for this step, mix on low speed with the paddle attachment.

Prepare the Blueberries

In a small bowl, toss the blueberries with 1 tablespoon of flour. This helps prevent them from sinking to the bottom of the cake.

Assemble the Blueberry Coffee Cake

Pour half of the batter into the greased baking dish.

Sprinkle half of the blueberries over the batter.

Sprinkle half of the crumb topping evenly over the blueberries.

Pour the remaining batter over the first layer.

Top with the rest of the blueberries and finish with the remaining crumb topping.

Bake the Cake

Place the baking dish in the preheated oven.

Bake for 40–50 minutes, or until the edges are golden brown, the center is set, and a toothpick inserted in the middle comes out clean.

Remove the cake from the oven and let it slightly cool on a wire rack before slicing and serving.

Tips for the Best Potato Flake Sourdough Blueberry Crumb Cake

• Use Room Temperature Ingredients: Eggs, milk, and yogurt should be at room temperature to blend smoothly. This is especially helpful to prevent the coconut oil from hardening and clumping up in the cake batter.
• Don’t Over mix the Batter: Over mixing can lead to a dense cake. Gently fold in ingredients until just combined.
• Test for Doneness: Start checking at the 40-minute mark to avoid over baking. Baking time varies from oven to oven so it can be a bit different for each person.
• Store Leftovers Properly: Keep the cake in an airtight container at room temperature for up to 3 days or refrigerate for up to a week.

Serving Suggestions

• Enjoy a slice warm with a hot cup of coffee or tea.
• Drizzle with a simple vanilla glaze for extra sweetness.
• Serve with a dollop of whipped cream or a scoop of vanilla ice cream.

​Baking Schedule

If you want to bake this delicious coffee cake first thing in the morning, you will want to prep the batter the night before.

It wil be fermented and ready to bake when you wake up, making a super easy and delicious breakfast without too much work. You will simply add the final ingredients and layer the cake-then it is ready to bake.

Fresh Blueberries vs. Frozen Blueberries

Both fresh and frozen blueberries work well in this recipe, but each has its advantages:

• Fresh Blueberries: They hold their shape better and provide a firmer texture in the cake. They’re great if blueberries are in season and readily available.
• Frozen Blueberries: These are a convenient year-round option. To prevent them from bleeding into the batter, do not thaw them before use. Tossing them in a tablespoon of flour helps distribute them evenly throughout the cake.

If you want a clean, visually appealing cake with distinct blueberry pockets, fresh blueberries are the best choice. But if convenience and availability are priorities, frozen blueberries will still deliver delicious results! 

Plain yogurt vs. Sour cream

Many of my recipes call for plain yogurt. You can get very similar results using sour cream. So why do I choose to use yogurt? 

I choose to make most of my recipes with yogurt because I make my own homemade yogurt in my instant pot making it a very affordable option for my family. 

Once you start making yogurt at home, you can continue making it with milk and a couple scoops of yogurt from your previous batch. Which means I can essentially make a gallon of yogurt for the price of a gallon milk.  

If you want to learn how to make your own homemade yogurt, I have a blog post written on how to do that! 

Some recipes on the blog that use my homemade yogurt:

Blueberry muffins

Chocolate cake

Double Chocolate Muffins

​Pumpkin Muffins

Do I have to ferment the batter?

In short, the answer is no. You do not have to ferment the batter. You can mix everything together, skip the fermentation and bake right away. However, I would not recommend doing this unless you are in a time pinch. The fermentation process creates coffee cake that is much easier to digest because of the fermented ingredients. It also creates a distinct flavor that adds to the deliciousness of the blueberry coffee cake. Skip it if you must, but a simple night before planning can help you avoid a last minute bake! 

This Potato Flake Sourdough Blueberry Crumb Cake is a wonderful way to use up sourdough discard while creating a sweet, satisfying treat. With its rich, tender crumb, bursts of blueberry flavor, and crunchy cinnamon topping, this cake is sure to become a favorite in your home!

If you love this blueberry coffee cake, I know you will love my Potato Flake Sourdough Blueberry Muffins too! It is a very similar batter and crumb topping. These are favorite among all of my family and friends!

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