Sourdough Blondies

These brownies have been well received by my readers and it occurred to me that we could very easily make sourdough blondies as well! I always put the recipe in question before myself though: why use sourdough to make blondies? I knew from these sourdough chocolate chip cookies the discard gives the cookies a wonderfully chewy texture and that would be a welcome contribution to a good blondie. That was enough for me to give it a try. 

What stood out to me though, was that the sourdough lightened up the flavor and yet gave the blondies both a chewy and denser texture, without the addition of extra butter and sugar. 

Recipe Origins

This recipe is, in many ways, a mix of two of last year’s sourdough discard recipes: sourdough chocolate chip cookies and sourdough brownies. From the cookie recipe I’ve taken how the butter and sugar are melted (this is what gives the blondies their sheen, crinkly crust) and given the dough a little rest before baking so the texture will be chewy. From the brownies, much of the quantities for the ingredients are the same with the obvious lack of cocoa and increased amount of flour. 

Recipe Ingredients 

Butter: unsalted butter, cold is fine. You can also use salted butter, just reduce the amount of salt added to the dough. 

Brown sugar: light or dark brown sugar. I used light here but dark would probably be even better: more chew, more butterscotch flavor. 

Egg: one whole egg and two egg yolks from large eggs. Reserve the whites for another use, like this! 

Vanilla: pure vanilla extract or vanilla bean paste. 

Salt: fine sea salt. 

Sourdough discard: unfed starter (it can be up to a week old, if kept in a sealed container). 

Flour: all purpose flour. 

Chocolate: semi-sweet, dark or milk chocolate chips depending on preference. Chopped chocolate is even better – just choose something you enjoy eating! 

How to make Sourdough Blondies

Partially melt the butter: set the butter in a heatproof bowl and microwave it until it’s half melted (don’t let any butter sputter out of the bowl). 

Over the partially melted butter, add the brown sugar, salt and vanilla and whisk to combine, for at least a minute: 

Heat the mixture: set the mixture back in the microwave for a minute at 100% power. This will fully melt the rest of the butter and begin to melt the sugar. 

Whisk for a few minutes, as you whisk notice the mixture turning from loose and matte to thick and shiny: 

Add the egg yolks and egg, whisk very well: until the egg and yolk are well incorporated. 

Measure in the discard and whisk until no white streaks remain: 

Stir in the flour: until fully combined. 

Seal the bowl with plastic wrap and set in the fridge for an hour. You can leave it longer, if you prefer but an hour at least.  

Preheat the oven and line an 8 or 9 inch square pan with parchment paper: lay two sheets of parchment paper over each other so all sides of the pan are covered in a + shape: 

Fold in the chocolate: after chilling the dough will be thick. If it’s too hard to mix in the chocolate (this will happen if you’ve left it longer than an hour) let it rest at room temperature for 10 minutes then try again. Mix until fully combined. 

Spread the blondie batter into the pan: because the batter is thick this is a little tricky but do your best to push it into the edges and smooth it into an even layer. 

Bake until puffed in the center, and golden on the edges: 25-35 minutes, depending on the size of your pan and how cold the dough was when it went into the oven. Look for puffiness in the center and some possible cracking. Don’t wait for it to brown on top, this will overcook the middle. 

Cool, then slice into 16 pieces that are about 2 inch squares. 

FAQ on Sourdough Blondies 

How to store the blondies? 

At room temperature in an airtight container they’ll last up to four days. If you’d like to store them longer, store them in the freezer – remove the air from the bag before freezing! 

Can I double the recipe? 

Yes, you’ll bake them in a 9 x 13 inch sheet cake pan. Rest the dough for double the time instructed below. Bake time will vary, but check them at 30 minutes and look for a puffed up center and golden edges. 

Can I make the dough ahead of time? 

You can (and I think it would work really well here!). Store the dough in the fridge, sealed with plastic wrap or in an airtight container for up to 48 hours before baking. I will note that adding the chocolate to the dough after a longer chill will be difficult – you can add it after 30 minutes of chilling (we’re trying to prevent the heat of the dough from melting it) or bring the dough to room temperature then stir in the chocolate. 

Sourdough Blondies Recipe

Sourdough Blondies

Brown sugar blondies with a shiny crinkle top made with sourdough discard. Discard gives these blondies a denser chewier texture.

Prep Time: 20 minutes mins

Cook Time: 30 minutes mins

Chill Time: 1 hour hr

Yields: 16 blondies

5 from 2 votes

Print Recipe Pin Recipe

Ingredients

• 170g or ¾ cups butter unsalted
• 260g or 1 ⅓ cups brown sugar light or dark
• 2 tsp pure vanilla extract
• ¾ tsp fine sea salt
• 2 egg yolks from large eggs
• 1 whole large egg
• 90g sourdough discard or unfed starter
• 205g or 1 ⅓ plus ¼ cup all purpose flour
• 150g or 1 cup chocolate chips more or less if you like

Method

• Set the butter in a heatproof bowl. Heat it in the microwave (use a microwave plate to stop the butter from sputtering out) until it’s partially melted.
• Add the brown sugar, salt and vanilla to the bowl and whisk very well, for about a minute.
• Return the bowl to the microwave and heat for 1 minute. Whisk the mixture very well, it will start as loose and separated and as you whisk turn to a thick and shiny mixture - don’t stop whisking until you see this transition.
• Add the egg yolks and egg and whisk well. Add the sourdough discard and whisk until it’s well combined.
• Stir in the flour. The batter will be warm and loose, cover the bowl with plastic wrap to seal and set it in the fridge for 45-60 minutes. Or, leave it overnight if you prefer.
• Preheat the oven to 350 F. Grease then line an 8 or 9 inch square pan with parchment paper, use metal clips to hold the paper in place.
• Stir the chocolate into the batter (we add it when the batter is cool so the chocolate doesn’t melt) and spread into the prepared pan. Nudge the batter into the corners of the pan and smooth it into an even layer.
• Bake the blondies until the edges are golden and the center has puffed, about 30 minutes. If you’ve done the heating and whisking correctly, you’ll see a lovely shiny top formed on top.
• Out of the oven the blondies will deflate, once cool you can remove them from the pan to slice and serve.

Did you make this recipe?

Share & tag me on instagram @buttermilkbysam

7 comments