Name: Sourdough Blueberry Buckle
Prep time: 20 min
Cook time: 45 min
Total time: 65 min
Ingredients: 60 g Granulated Sugar ((can use white sugar)); 60 g Brown Sugar; 50 g All Purpose Flour; 1 g Cinnamon ((approx. 1 tsp - can add more if you like)); 60 g Butter ((cubed, cold)); 60 g Butter ((softened or melted - see notes)); 1 Egg ((use 2 if your eggs are on the small side)); 150 g Sourdough Starter ((or sourdough starter discard)); 150 g Milk ((or can use buttermilk)); 5 g Vanilla Extract ((optional)); 200 g All Purpose Flour; 10 g Baking Powder; 5 g Salt; 160 g White Sugar; 1 Lemon (zest only); 300 g Blueberries ((fresh or frozen - see notes))

You are going to love this sourdough blueberry buckle! This family favorite features juicy blueberry goodness surrounded by a sourdough based sponge cake, topped with a cinnamon brown sugar streusel. It's a kind of sourdough blueberry crumb cake that is equally at home on your breakfast table with a cup of coffee or served as a sourdough discard dessert. Love some good versatility!

If you love this recipe, then you might also enjoy this sourdough coffee cake or this sourdough strawberry cake, or even this sourdough lemon and blueberry loaf.

Sourdough blueberry buckle that has been sliced and stacked to display the beautiful purple blueberries inside.

Why You'll Love This Recipe!

Super Easy - While this sourdough blueberry buckle does have a lot of ingredients, it's super easy to put together. The longest part of the recipe is actually waiting for it to bake!

Fresh or Frozen - You can use fresh or frozen blueberries for this recipe making it accessible all year round, even when it's not blueberry season. I've chosen to use frozen blueberries in all the photos you'll see here.

Breakfast or Dessert - I love that this easy sourdough recipe is equally at home on your breakfast table as it is on your dessert table (just add ice cream).

A slice of sourdough blueberry buckle sitting on a blue plate. There is a pink cake pan in the background.

What is a Buckle?

A buckle is a rustic, old-fashioned cake that features a rich, buttery batter layered with fresh or frozen fruit and topped with a crumbly streusel topping. As it bakes, the cake "buckles" around the juicy fruit, creating an uneven, craggy surface that gives this dessert its name (seriously how cool is that).

Unlike a sourdough apple crisp or sourdough berry cobbler, where the fruit is the primary focus, a buckle has a more cake-like structure, though the fruit remains a prominent and flavorful component. Blueberry buckle is one of the most popular variations, but this versatile treat can be made with a variety of fruits, such as peaches, apples, or cherries, depending on what is in season.

Perfect for breakfast, brunch, or dessert, a buckle is best enjoyed warm, often with a dusting of powdered sugar or a scoop of vanilla ice cream (sign me up).

Bowl of frozen blueberries dusted in flour.

Ingredients

There are quite a few ingredients necessary to make a sourdough blueberry buckle, but don't let this list put you off. It really is a throw it in the bowl, mix and bake type cake once you've got everything out on the counter.

Sugar - you'll need a mixture of brown sugar and granulated or white sugar for the streusel topping and white sugar for the cake batter.
All Purpose Flour - you'll be using all purpose flour to create the cake batter as well as the crumble topping.
Cinnamon - approximately a teaspoon of ground cinnamon is used in the streusel topping to make it taste absolute delicious!
Butter - you'll need cubed, cold butter for the streusel topping and softened butter for the cake batter. Of course, as always, I've used salted butter, but you can choose to use unsalted if you prefer.
Egg - I've use a lovely fresh egg from my chickens. I have not tried this recipe with any egg free alternatives. If your eggs are on the small side I recommend using 2 eggs instead of 1.
Sourdough Starter - I've used active sourdough starter to create this recipe. You can use sourdough discard if you prefer. It doesn't really matter which you use because you'll be using baking powder for the leaving of this cake. You can read about the differences between sourdough discard and sourdough starter here.
Milk - I've used whole milk but you can use any milk you have on hand. Even non dairy milk is fine in this recipe. Buttermilk is also a great substitute for regular milk too!
Vanilla Extract
Baking Powder + Salt - the baking powder provides the leavening for the cake, not to be confused with baking soda!
Lemon Zest - I've added the zest of a lemon to add some freshness to the recipe. You don't have to add the lemon zest, but I recommend it. You could also substitute this with orange zest if you prefer.
Blueberries - I've used frozen blueberries for the sourdough blueberry buckle you'll see photographed in this post, but you can use fresh blueberries if you prefer. I love the way that frozen blueberries take on an almost jammy consistency once they're baked. Make sure you read the notes in the recipe card in relation to tossing the frozen blueberries in flour, as well as the amount of blueberries I've used!

Flat lay of ingredients necessary to make a sourdough blueberry buckle.

How to Make Sourdough Blueberry Buckle

I've created this recipe to be made with just a bowl and a whisk, rather than having to use a stand mixer or hand mixer (of course you can use them if you want to). This is a moist cake with a light crumb, without having to whip the butter and sugar together. I love being able to just throw this together with minimal equipment! It's even a great recipe to get the kids in the kitchen too!

Before you start, preheat your oven to 200C (390F) and lightly butter or spray with oil a 9" x 9" cake pan.

Make the Streusel Topping

Add the granulated sugar, brown sugar, all purpose flour and cinnamon to a small mixing bowl. Mix these together until well combined.

Now add the cold, cubed butter to the top of this mixture. Use your finger tips to rub the dry mixture into the butter until it resembles bread crumbs. It's ok if there are some clumps of butter still.

Set this aside while you make the cake batter. If your kitchen is warm, pop this streusel topping in the freezer (side note here, this streusel topping is absolutely delicious on these sourdough banana muffins). Make a double batch and give it a go!

Cake Batter

Now mix the wet ingredients together in a bowl. Add the softened butter, egg, sourdough starter, milk and vanilla extract to a bowl and whisk until well combined (don't worry if the butter goes a bit lumpy). Set this aside.

Next, combine the dry ingredients, excluding the blueberries, in a bowl and mix until well combined.

Pour the wet ingredients into the dry ingredients. Mix together using a spatula until a light cake batter is formed. Set this aside.

Now if you're using frozen blueberries you'll need to toss these in around 20g of flour before you use them. Do this now and then pop them aside while you assemble the cake. You can see in the photos that I've chosen to use frozen blueberries rather than fresh.

A glass bowl of frozen blueberries tossed in flour alongside a blue batter jug containing a brown sugar cinnamon streusel mixture.

Assemble the Cake

Now take the cake pan you prepared earlier and spread half the cake batter on the base. Then spread half the blueberries across the cake batter. Spread the rest of the cake batter over the blueberries and then add the remaining blueberries over this so you should have now used up all of the batter and blueberries. Remember the cake will rise up and buckle around the fruit.

Sprinkle all of the streusel topping over the top of the blueberries and batter and then place the sourdough blueberry buckle into the oven and bake for around 45 minutes at 200C (390F).

You'll know the sourdough buckle is done when the streusel topping is golden brown and a skewer comes out clean when inserted into the middle of the cake.

You can serve this cake warm straight out of the pan. To do this, I just use a lasagne server to cut and lever the warm buckle out. If you want to slice it evenly, I find it's best to wait until it's cool and then remove from the pan and slice with a serrated knife.

Two slices of sourdough blueberry buckle sitting on top of each other on a stack of plates. — The sourdough blueberry buckle in this photo has been cut from a cooled cake with a serrated knife. It has a less fluffy texture than when served warm straight from the pan.

How To Store + Freeze

This delicious sourdough blueberry buckle can be baked and eaten within 3 days. I find it's best to store in an airtight container in the fridge. You can either eat it cold or allow it to sit at room temperature for a little bit. If you prefer it warm, you can reheat it in the microwave.

This sourdough blueberry buckle can be frozen. Wrap portions in plastic wrap or place in ziploc bags and freeze for up to 2 months.