Name: Sourdough Discard Blueberry Loaf with Lemon Glaze
Prep time: 15 min
Cook time: 50 min
Total time: 110 min
Ingredients: 240 g all-purpose flour (2 cups); 8 g baking powder (2 tsp); ½ tsp fine salt; 113 g butter (½ cup / 1 stick, melted and slightly cooled); 200 g granulated sugar (1 cup); 2 large eggs (room temperature); 1 tsp vanilla sugar (or vanilla extract); 170 g plain Greek yogurt (¾ cup, full fat); 120 g sourdough discard (½ cup, unfed, straight from the fridge); 400 g fresh blueberries (2¾ cups); 1 tbsp all-purpose flour (for tossing the berries); 300 g powdered sugar (2½ cups); 1 lemon, juced (about 3 tbsp / 45 ml); 1 lemon, zested (the same lemon — zest it before you juice it)

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This sourdough discard blueberry loaf is what a fridge full of unfed starter is for. It’s a soft, buttery loaf cake packed with berries and finished with a sharp lemon glaze — no proofing, no schedule, just batter that goes straight into the pan. If you bake sourdough, you already have the one ingredient that makes it interesting.

Sourdough Discard Blueberry Loaf with Lemon Glaze

A sourdough discard blueberry loaf with a tender, berry-marbled crumb and a tangy lemon glaze — sweet, simple and made with unfed starter straight from the fridge.

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Prep Time 15

Cook Time 50

Cooling 45

Total Time 1 50

Servings: 15 slices

Course: Dessert, Snack

Cuisine: Nordic

Ingredients Equipment Method Notes

Ingredients

Batter

240 g all-purpose flour 2 cups
8 g baking powder 2 tsp
½ tsp fine salt
113 g butter ½ cup / 1 stick, melted and slightly cooled
200 g granulated sugar 1 cup
2 large eggs room temperature
1 tsp vanilla sugar or vanilla extract
170 g plain Greek yogurt ¾ cup, full fat
120 g sourdough discard ½ cup, unfed, straight from the fridge

Berries

400 g fresh blueberries 2¾ cups
1 tbsp all-purpose flour for tossing the berries

Lemon glaze

300 g powdered sugar 2½ cups
1 lemon, juced about 3 tbsp / 45 ml
1 lemon, zested the same lemon — zest it before you juice it

Equipment

9×5-inch metal loaf pan This is a full pan of batter, so you want the larger size — a 9×5 (2 lb / 8-cup) metal pan. Chef-tested pick for US kitchens.
Digital kitchen scale With 400 g of berries in a single loaf, weighing the flour is what keeps the crumb from going heavy.
Silicone spatula Folds the blueberries in without crushing them — a wooden spoon will streak the batter purple.
Fine zester / rasp grater Fine zester / rasp grater
Wire cooling rack The loaf has to be completely cool before it's glazed, or the glaze soaks in and disappears.
Parchment paper A parchment sling lifts a berry-heavy loaf out in one piece.

Method

Heat the oven to 350°F / 180°C. Line a 9×5-inch loaf pan (8-cup / 2-litre capacity) with parchment, leaving an overhang on the long sides.
Whisk the flour, baking powder and salt together in a bowl and set aside.
In a large bowl, whisk the melted butter and sugar until smooth. Add the eggs one at a time, then the vanilla, yogurt and sourdough discard. Whisk until the batter is even and glossy.
Fold in the dry ingredients with a spatula, stopping as soon as no dry flour is left. The batter should be thick and a little lumpy — don't beat it smooth.
Toss the blueberries with 1 tbsp flour, then fold them in gently, holding back a small handful to scatter over the top.
Scrape the batter into the pan, level the surface and scatter the reserved berries on top. Bake for 50–60 minutes, until a skewer in the centre comes out clean. If the top colours before the middle is set, tent it loosely with foil.
Cool in the pan for 15 minutes, then lift the loaf out by the parchment and let it cool completely on a rack.
Zest the lemon first and set the zest aside, then juice it. Whisk the powdered sugar with the lemon juice a spoonful at a time until you have a thick, slow-pouring glaze — it should coat the whisk and fall off in a ribbon, not run like water. Pour it over the cooled loaf, let it spill down the sides, and scatter the zest over the top while it's still wet.

Notes

Chef’s tip — use the discard cold and unfed. This is one of the few sourdough bakes with no guesswork: the baking powder does all the lifting, so the discard is there purely for flavour and acidity. Straight from the fridge is exactly what you want — no feeding, no waiting for it to peak, no wondering if it’s active enough.

That acidity is also why the crumb stays tender. Between the discard and the yogurt, this loaf is better on day two than it is on day one. Keep it covered at room temperature for up to three days.

Why so many berries? 400 g in one loaf is deliberate — it’s what gives you the marbled crumb instead of a few berries scattered through plain cake. It also means a longer bake, so trust the skewer rather than the clock. Tossing the berries in flour keeps them suspended instead of sinking to the bottom.

Frozen blueberries work. Don’t thaw them, and add 5 minutes to the bake time.

A note on the glaze. This is a generous, opaque white glaze — enough to cover the whole top and run down the sides, which is how it looks in the photo. Lemons vary a lot in juice, so add the juice gradually rather than all at once: too thin and it soaks in instead of setting. If you’d rather have a thin drizzle, make half.

A note on the pan. This makes a generous 9×5 loaf — about 8 cups of batter and berries. If your pan is smaller split the batter between two smaller loaf pans and bake for about 40 minutes instead. Two shallower loaves bake more evenly with this much fruit, and you get a second one to give away.

Why sourdough discard belongs in a sweet cake

Discard gets treated like a leftover to be used up, but in a cake it’s doing real work. It brings acidity, and acidity does two things here: it softens the crumb, and it cuts through 200 g of sugar so the loaf tastes bright rather than flat. It’s the same reason buttermilk cakes work.

What it isn’t doing is lifting anything. The baking powder handles that. So take the discard cold and unfed straight from the fridge — this is the one sourdough bake where you don’t have to think about whether your starter is happy.

Tips for the best sourdough discard blueberry loaf

Toss the berries in flour. One tablespoon is enough. Skip it and most of them end up in a purple layer at the bottom.

Stop mixing early. Fold the dry ingredients in until they just disappear. A slightly lumpy batter bakes into a tender loaf; a smooth, beaten one bakes into a tough one.

Bake to the skewer, not the timer. With this much fruit, the centre stays wet longer than you’d expect. 50 minutes is the earliest it’ll be done, 60 is normal, and a foil tent buys you time if the top is already dark.

Glaze it cold. Completely cold. Warm loaf, and the glaze sinks in and vanishes instead of setting into that white crackle you want on top.

Make it your own

Raspberries or blackcurrants work in place of blueberries — both are sharper, so pull the sugar back by a couple of tablespoons. Swap the lemon for orange in the glaze if you want something rounder and less tart. And if you’d rather skip the glaze entirely, a scatter of coarse sugar over the batter before baking gives you a crisp, cracked top instead.

Sourdough Discard Blueberry Loaf with Lemon Glaze