Gluten-Free Sourdough Discard Miso Caramel Blondies
Miso caramel turns an ordinary blondie into something you will be asked to make again. These bars use gluten-free sourdough discard in place of some of the liquid, the same way discard shows up in pancakes or banana bread elsewhere on this site, for flavor and moisture rather than any rise. White miso paste stirred into the caramel swirl adds a savory, almost nutty backbone that keeps the whole pan from tasting like straight sugar.
This one comes together the same afternoon you bake it, no starter feeding schedule to plan around and no overnight proof. If you keep a jar of gluten-free discard in the fridge that needs using, this is one of the easiest ways to put a cup of it to work.
Why You’ll Love It
- No overnight planning. Mix the batter, swirl in the caramel, and bake, all in one afternoon.
- A real use for gluten-free discard. A full cup goes into the batter instead of sitting in the fridge.
- Savory meets sweet. White miso in the caramel swirl keeps the bars from tasting one-note.
- Chewy, not cakey. The blondie base bakes dense and fudgy, closer to a brownie than a cake.
- Freezes well, cut or whole. Portion the pan and pull out a square whenever the craving hits.
Ingredients
Volume measurements are included for convenience, but they’re approximate. Weigh the flour especially, gluten-free blends pack differently than regular flour and a scooped cup can run heavy.
Blondie Batter
- Unsalted butter, melted (113 g (about ½ cup / 1 stick)): creamed with the sugars for a chewy, dense crumb typical of a blondie.
- Light brown sugar, packed (150 g (about ¾ cup)): the backbone of a blondie’s caramel flavor, packing it tight matters for an accurate measurement.
- Granulated sugar (50 g (about ¼ cup)): balances the brown sugar’s molasses notes with straightforward sweetness.
- Egg (50 g (about 1 large)): binds the batter and adds richness.
- Active gluten-free sourdough discard (100 g (about about ½ cup)): unfed straight from the fridge is fine here, it’s for flavor and moisture, not lift.
- Vanilla extract (6 g (about 1½ teaspoons)): rounds out the caramel notes.
- King Arthur Gluten-Free All-Purpose Flour (180 g (about about 1½ cups)): a wheat-starch-free blend that keeps the crumb from turning gummy, see Desi’s Notes if you only have the Bread Flour blend.
- Baking powder (4 g (about 1 teaspoon)): the only lift this bar needs, there’s no yeast activity at play.
- Fine salt (3 g (about ½ teaspoon)): balances the sweetness across the whole pan.
Miso Caramel Swirl
- Unsalted butter (56 g (about 4 tablespoons)): the base of the caramel.
- Light brown sugar, packed (65 g (about ⅓ cup)): cooked down with the butter until it turns glossy.
- Heavy cream (60 g (about ¼ cup)): loosens the caramel so it swirls instead of sitting in a hard pool.
- White miso paste (30 g (about about 2 tablespoons)): adds a savory, fermented depth that plays off the sweetness instead of hiding from it.
- Flaky sea salt, for finishing (3 g (about about ½ teaspoon)): a pinch scattered over the top right after baking makes the miso caramel pop against the sweet crumb.
Equipment
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- Kitchen scale: for weighing the flour, discard, and caramel ingredients.
- 9×9-inch metal baking pan: the right size for bars this thick, a bigger pan will bake thinner and dry out faster.
- Parchment paper: lines the pan so the whole slab lifts out clean for cutting.
- Medium saucepan: for cooking the miso caramel on the stovetop.
- Large mixing bowl: for creaming the butter and sugars and mixing the batter.
- Whisk: for whisking the dry ingredients together.
- Rubber spatula or butter knife: for swirling the caramel through the batter.
- Cooling rack: lets the pan cool evenly before the bars are cut.
Sample Schedule (Same Day)
Same Day
- Make the miso caramel and let it cool slightly
- Cream the butter and sugars, then mix in the egg, discard, and vanilla
- Whisk the dry ingredients and fold them in
- Spread the batter in the pan and swirl in the caramel
- Bake until set, about 28 to 32 minutes
- Cool completely, then finish with flaky salt and cut
Gluten-Free Sourdough Discard Miso Caramel Blondies
Method
- Melt the butter, brown sugar, cream, and miso together until smooth and glossy. Cool slightly.
- Whisk the melted butter with the brown sugar and granulated sugar until smooth.
- Whisk in the egg, then the discard and vanilla.
- Whisk the flour, baking powder, and salt together.
- Fold the dry ingredients into the batter until just combined.
- Spread the batter into a parchment-lined 9×9-inch pan.
- Drizzle the caramel over the batter and swirl with a knife.
- Bake at 350°F for 28 to 32 minutes, until golden with a few moist crumbs on a toothpick.
- Cool completely in the pan before cutting.
- Lift out, finish with flaky salt, and cut into 16 squares.
Notes
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How to Make It
1Make the miso caramel. In a medium saucepan over medium heat, melt the butter with the brown sugar, cream, and miso paste, whisking constantly until smooth and glossy, about 3 minutes. Set aside to cool slightly. Whisk the miso in well, it likes to clump at first against the hot butter. The caramel should coat the back of a spoon and look like wet sand in color by the time it’s ready. Let it cool for about 10 minutes so it doesn’t melt straight into the batter when you swirl it in.
2Cream the butter and sugars. In a large bowl, whisk the melted butter with the brown sugar and granulated sugar until smooth and a shade lighter. Since the butter is melted rather than softened, this will look more like a thick paste than the fluffy, aerated mixture you’d get from creaming cold butter, and that’s exactly the texture a chewy blondie wants. Give it a full minute of whisking so the sugar starts to dissolve into the fat.
3Mix in the egg, discard, and vanilla. Whisk in the egg, then the gluten-free sourdough discard and the vanilla extract, until the batter looks smooth and slightly lighter in color. The discard does not need to be bubbly or recently fed for this recipe, straight from the fridge is fine since it’s working for flavor and moisture, not for any rise. The batter will loosen up noticeably once the discard goes in, don’t worry if it looks thinner than a typical blondie batter at this stage.
4Whisk the dry ingredients. In a separate bowl, whisk together the gluten-free flour, baking powder, and salt. Whisking the dry ingredients on their own first, rather than dumping them straight into the wet batter, keeps the baking powder from clumping in one spot and leaving a bitter bite in a stray corner of the pan.
5Fold the dry ingredients in. Add the dry ingredients to the wet batter and fold with a spatula just until no dry streaks remain. Stop folding as soon as the flour disappears. Gluten-free blends don’t develop gluten the way wheat flour does, but overworking the batter can still make the bars gummy instead of tender. The finished batter will be thick, closer to cookie dough than a pourable cake batter.
6Spread the batter in the pan. Line the 9×9-inch pan with parchment paper, leaving an overhang on two sides, then spread the batter evenly into the pan. The parchment overhang is what lets you lift the whole slab out in one piece later instead of digging bars out of the pan. Push the batter all the way into the corners, it’s thick enough that it won’t level itself the way a thinner batter would.
7Swirl in the miso caramel. Drizzle the cooled miso caramel over the batter in lines, then drag a butter knife through in a zigzag pattern to swirl it through the top. Don’t overmix the swirl, a few decisive passes of the knife give you defined ribbons of caramel instead of blending it fully into the batter and losing the marbled look. Save a spoonful of caramel back if you’d like a few extra pools on top.
8Bake until set. Bake at 350°F for 28 to 32 minutes, until the top is golden and a toothpick inserted in the center comes out with a few moist crumbs. The center will look slightly underdone compared to the edges when you pull it, and that’s what you want for a fudgy blondie, it firms up as it cools. A toothpick that comes out fully clean usually means the bars have gone past fudgy into dry.
9Cool completely. Let the pan cool completely on a rack before lifting out the slab and cutting. Blondies this fudgy need the full cool to set up, cutting warm gets you a gooey mess instead of clean squares. If you’re in a hurry, the freezer can take the last 20 minutes off, about 30 minutes in should do it.
10Finish and cut. Lift the slab out using the parchment overhang, scatter flaky salt over the top, and cut into 16 squares. A thin, sharp knife wiped clean between cuts gives you the neatest edges, the caramel swirl tends to drag otherwise. The flaky salt matters more than it looks like it would, it’s what keeps the first bite from reading as purely sweet.
Tips & Troubleshooting
- Bars came out cakey instead of fudgy: the batter was overbaked. Pull them at the moist-crumb stage on the toothpick, they firm up a lot while cooling.
- Miso caramel tasted too salty: not all miso pastes are the same strength. Start with 20 g if yours is on the saltier side, then taste before adding the rest.
- Bars stuck to the pan: the parchment didn’t reach the corners, or there wasn’t enough overhang to grip. Cut the parchment a few inches larger than the pan on two sides.
- Caramel sank to the bottom instead of swirling through: it was too warm and thin when it went on. Let it cool closer to room temperature before drizzling it over the batter.
How to Store
To store: Keep the bars in an airtight container at room temperature for up to 4 days. The caramel swirl stays soft even after a few days, which keeps the bars from drying out.
To freeze: Wrap individual squares and freeze for up to 2 months. Thaw at room temperature for about 20 minutes, or microwave one for 10 seconds for a warm, gooey bite.
Nutrition
Nutrition is estimated per square, for a pan cut into 16 squares, and will vary with the exact miso paste and flour blend used.
210
CALORIES
27g
CARBS
2g
PROTEIN
10g
FAT
6g
SAT. FAT
1g
FIBER
17g
SUGAR
150mg
SODIUM
Desi’s Notes
This recipe is Research-backed. It follows the same batter method as the site’s other gluten-free sourdough discard treats, with a savory miso caramel swirled through a fudgy blondie base. It has not been through a Bake-Keeper kitchen test yet.
Miso in a dessert still surprises people the first time, so I’ll say the obvious part out loud. You are not tasting miso the way you would in soup, you’re tasting a deeper, rounder caramel that doesn’t read as salty or fermented on its own. It just makes the sweetness taste more finished.
If you only keep King Arthur’s Gluten-Free Bread Flour Blend on hand instead of the All-Purpose Blend, you can use it here, the bars will come out very slightly denser since that blend includes wheat starch for structure. Either way, weigh the flour rather than scooping it.
Before You Bake
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