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These sourdough blondies have everything you want in a dessert bar – a crackly top, gooey center, and rich caramel flavor from dark brown sugar. Studded with white chocolate chips and made with sourdough discard or active starter, they’re one of the easiest sourdough desserts you’ll ever bake. The best thing? They’re made with simple ingredients you probably already have in your pantry!
Table of Contents
Why You’ll Love This Recipe!
To me, these blondies are the perfect cross between sourdough chocolate chip cookies and sourdough brownies. They are the ultimate dessert bar and have become one of my absolute favorite things (I’m definitely a sweet tooth!).
Perfect Gooey Blondie – A good blondie has a denser texture, like a good brownie, but with a more caramel flavor. You’ll love these perfect gooey blondies, with the classic flavors of brown sugar and white chocolate chips that get caramelized as they bake. Is there anything better?
Cheap & Cheerful Sourdough Dessert – These sourdough blondies use basic pantry ingredients to create something truly delicious. There’s no need for large amounts of chocolate like a traditional brownie.
They Freeze Really Well – Sourdough Blondies freeze really well and are great to have in the freezer for “dessert emergencies”. I love to freeze as a whole block and then slice once thawed.
Ingredients
- Butter – Melted butter gives these blondies their rich flavor and chewy texture. I always use salted butter, but as always, you can use unsalted butter if you prefer.
- Dark Brown Sugar – This is what gives blondies their signature caramel and butterscotch flavor. I highly recommend using dark brown sugar if you can find it.
- Eggs – Separating the eggs and whipping the whites creates that gorgeous crackly top and soft texture, rather than just adding a whole egg to the mixture.
- Vanilla Extract
- Sourdough Starter – You can use active sourdough starter or sourdough discard. I prefer a thicker discard rather than one that’s very runny and acidic.
- All Purpose Flour
- Baking Powder + Baking Soda – I’ve used both to help create the perfect texture.
- White Chocolate Chips – I love the way white chocolate complements the caramel notes in these blondies.
How To Make Sourdough Blondies
These sourdough blondies are super easy to make. The most difficult thing you’ll need to do is whisk 2 egg whites until they form stiff peaks. The rest is relatively easy!
Kate’s Pro Tip
Sourdough Discard or Active Sourdough Starter?
You can use either sourdough discard or active sourdough starter for this recipe. I’ve tested this recipe extensively and one thing I’ve discovered yields the best results is thicker sourdough starter or discard. So if you are using discard, make sure it’s not too runny and sour as it will create an unpleasant sourness in these blondies, rather than a subtle tang.
Sourdough discard is the same as sourdough starter, it’s just the unfed portion you remove from the jar before you feed it, so using either one is perfectly fine. You can find more definitions on all things sourdough in this sourdough glossary.
Simply whisk the egg whites until stiff peaks form and set them aside. Mix the melted butter and brown sugar together, then add the egg yolks and vanilla.
Kate’s Pro Tip
Brown Sugar Tip
This recipe calls for 220g of dark brown sugar to ensure you get the sweet butterscotch flavor blondies are renowned for. If you don’t have dark brown sugar, you can use light brown sugar and add 20g of molasses to make up for the flavor.
If you really love those deep caramel flavors, you can use dark brown sugar and molasses. YUM!
Stir in the flour, sourdough starter, baking powder, baking soda, salt, and white chocolate chips (basically all the dry ingredients).
Then gently fold in the egg whites.
Spread the blondie batter into a parchment paper-lined baking pan using a spatula and bake in a preheated oven until golden brown. It’s quite a thick mixture so you’ll need to spread it out evenly.
Once cooled, slice into squares and try not to eat them all at once. You can find a full set of instructions and detailed ingredient list in the recipe card further down.
Flavor Additions for Sourdough Blondies
I love adding white chocolate chips to these sourdough blondies, but there’s no limit to the ingredients or flavor additions that you can add to these gooey sourdough discard blondies. Here are a few ideas:
- Chocolate Chunk Blondies – Add 100g of chopped semi-sweet chocolate for the ultimate caramel chocolate indulgence.
- Walnuts, pistachios or Pecans – Chop up 100g of your favorite nuts for a crunchy addition to these sourdough discard blondies.
- Butterscotch Chips – Add 100g of butterscotch chips for an extra big hit of butterscotch sweetness.
- Brown Butter Blondies – Brown and cool your butter before making these sourdough blondies.
- Flaked Sea Salt – Sprinkle a little flaky sea salt on top of the sourdough blondies before baking. The addition of flaky sea salt is a fun little twist on this classic sourdough dessert.
How To Store + Freeze
These sourdough blondies will keep in an airtight container for 3 days.
You can easily freeze this sourdough dessert. You can freeze the blondies as a whole, so don’t cut them once baked, simply wrap in parchment paper and then foil and freeze for up to 3 months.
To freeze individual portions, cut into squares and then wrap each piece in parchment paper and then foil.
Allow to thaw at room temperature before enjoying.
Frequently Asked Questions
Yes! Sourdough discard works beautifully in this recipe and is my favorite way to use it.
You can. Add around 20g of molasses to help recreate the deeper flavor of dark brown sugar.
The blondies will still taste delicious if your chips sink, but using a thicker batter and gently folding the chips through at the end can help.
Absolutely. Pecans, pistachios or walnuts are all excellent additions.
Sourdough Blondies
Equipment
- Square Baking Tin (9 x 9 inches)
Ingredients
- 110 g Butter, (melted)
- 220 g Dark Brown Sugar , (see notes for light brown sugar)
- 2 Eggs, (separated into whites and yolks)
- 5 g Vanilla Extract
- 100 g Sourdough Starter, (active or discard)
- 3 g Baking Powder, (1/2 tsp)
- 3 g Baking Soda, (1/2 tsp)
- 3 g Salt, (just a pinch)
- 120 g All Purpose Flour
- 100 g White Chocolate Chips , (see notes for alternatives)
Instructions
- Preheat your oven to 350F (175C) and line a 9 x 9 inch square pan with baking paper (you can butter and flour the pan if you prefer).
- Whisk together the egg whites until stiff peaks form. Set aside while you assemble the other ingredients.
- Whisk together the melted butter and brown sugar (I've just used a fork for this step).
- Now add the egg yolks, vanilla and molasses (if you are using it) and whisk until combined.
- Now add the all purpose flour, sourdough starter, baking powder, baking soda, salt and white chocolate chips. Stir until they are just combined (don't over mix).
- Now gently fold in the egg whites until just combined.
- Pour the sourdough blondie batter into the prepared pan and place into the oven. Bake for 25 minutes at 350F (175C) until golden (insert a skewer into the blondies to see if it comes out clean).
- Allow the blondies to cool in the tin before cutting into squares to serve.
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Like this? Rate and comment below!
Anyway to make this vegan? What can I use?
I need to make these gluten free, have you tried this recipe with gf all-purpose flour? Any suggestions?
I’m sorry I haven’t tried them with gluten free flour but if you do, let me know how they turn out 🙂
Very tasty but these turned out cake-ier than expected and all my chocolate chips sank to the bottom. Where did I go wrong 😭
I made these minus the white choc chips and with the regular brown sugar I had in my pantry….. it’s delicious! And really quick and easy! I made and baked before school this morning!
It’d be heaven WITH The white choc chips! Will for sure be baking these again!
I made these with semi-sweet chocolate chips as I prefer them over white choc chips and they are delicious. They don’t have an overly sweet taste which we like. I also added chopped pecans. I’m looking forward to making a bigger batch soon and using them as food gifts to my family.
Easy to make and delicious! The white chocolate chips sank to the bottom but still very yummy.
Super easy and everyone loved it, next time im going to try making them in the brownie bit molds
In your directions you list molasses, but there is no measurement in your ingredients since the molasses isn’t even listed.
If you look in the notes, I have added a note about using molasses with light brown sugar in place of dark brown sugar 🙂 But thank you for pointing this out, I will change it so that it’s more clear 🙂 I hope you enjoy the recipe 🙂
The kids love these! They are really fluffy and taste good. Next time I make these I’ll also mix in some raspberries 🙂
I just made these for a group dinner and people were obsessed. I browned the butter as an extra oomf and added the white chocolate chips. It really was an easy and delicious recipe!
Amazing beginner recipe!!! Super easy to follow and love that it was quick. Made them last minute for dessert and my fiancé and I melted at the first bite. Highly recommend! Sourdough noms don’t have to be so scary!