Lemon poppyseed loaf sliced on plate showing super soft crumb.

Tangy Lemon Poppyseed Loaf

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Lemon poppyseed is one of those combinations we bakers never seem to tire of. Muffin or loaf; glazed or not, it’s a classic flavor profile that need not be improved upon. But could one challenge the classic just a smidge and make sourdough starter discard lemon poppyseed loaf? (Whew, a mouthful of a recipe name!) As is the case with most bakes that include flour and liquid, the answer is a resounding yes. 

With a caveat: Cakes like lemon poppyseed should have a moist, tender crumb (not at all chewy like bread); and their flavor should be tart, but not overly sour (like a sourdough loaf). To avoid a dense, chewy loaf, you should use less starter discard than you possibly could. When taking this into consideration, a lovely tea cake is in your future.

Golden crust on the lemon poppyseed loaf.
Golden poppy-studded deliciousness. Photo by Rebecca Firkser.

Use Unfed Discard Straight from the Refrigerator 

This cake rises thanks to baking powder and whole eggs, so they don’t need active sourdough starter for lift. Feel free to use unfed sourdough starter discard from the refrigerator cache, or the ripe version you’ve just discarded. 

To Remove Excess Water, Use Less Dairy

If you’ve made other lemon poppyseed loaf or muffin recipes, you know there’s often dairy included, typically something tangy to play with the lemon, like buttermilk, sour cream, or yogurt. I went with buttermilk for my first test of the recipe, which is mostly water, and replaced half of what I’d use in a regular oil-based buttermilk loaf cake. Because buttermilk has nearly no fat, much of which was then replaced with pure water, the cake lacked richness and the tanginess from the starter was more apparent. While I didn’t want the loaf to be overly rich (think: tea cake, not birthday cake!) I landed on plain whole-milk yogurt (85% water).

Slice of lemon poppyseed loaf showing tender interior.
You’ll love the tender texture and bright lemon flavor.

In early tests of this recipe, I tried omitting 1 egg white as well and replaced it with the water’s worth of starter discard. While egg whites are mostly water, when replaced with pure water in such a cake, the crumb lacked structure, making the cake more dense. It actually reminded me of cakes made with sweet rice flour, or mochiko; like a cross between butter mochi and a traditional oil-based cake. If the extra starter discard purely created this texture, I might’ve left the recipe alone. But the overt sour flavor from the additional starter discard took away from the delicate lemon flavor I always look for in lemon poppyseed cakes.

I also tried swapping in starter discard in place of 25 grams (2 tablespoons) lemon juice; again, I was met with a strong sour flavor, not the delicate floral tartness that citrus juice offers. Not worth it!

In the end, I found the right balance of flavor when I used just 110 grams (½ cup) sourdough starter discard, taking the liquid from some of the yogurt.

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Slice of lemon poppyseed loaf showing tender interior.

Tangy Lemon Poppyseed Loaf

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  • Author: Rebecca Firkser
  • Prep Time: 15 minutes
  • Cook Time: 1 hour 25 minutes
  • Total Time: 1 hour 40 minutes
  • Yield: One loaf
  • Category: Dessert
  • Cuisine: American
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A classic tart lemon cake with a moist, tender interior and tangy twist thanks to the added sourdough starter.


  • Cooking spray or neutral oil, for greasing the pan
  • 162 grams (1 ¼ cups plus 1 tablespoon) all-purpose flour
  • 12 grams (1 tablespoon) poppy seeds
  • 8 grams (2 teaspoons) baking powder
  • 2 grams (½ teaspoon Diamond Crystal or ¼ teaspoon Morton) kosher salt
  • 200 grams (1 cup) granulated sugar
  • 12 grams (2 tablespoons) lemon zest 
  • 100 grams (2 large) eggs
  • 57 grams (¼ cup) plain whole-milk yogurt
  • 66 grams (⅓ cup) neutral oil, such as canola
  • 25 grams (2 tablespoons) lemon juice
  • 110 grams (½ cup) sourdough starter discard (100% hydration, unfed)


  1. Heat the oven to 350ºF/175ºC with a rack in the center. Grease an 8 ½ x 4 ½-inch loaf pan with cooking spray or oil, then line with a piece of parchment paper, leaving at least a 1-inch overhang on the long sides.
  2. In a medium bowl, whisk together the flour, poppyseeds, baking powder, and salt.
  3. In a large bowl, add the sugar and zest. Use your fingers to rub the zest into the sugar until moistened and fragrant. Whisk in the eggs, yogurt, and oil until smooth. Whisk in the starter and lemon juice until smooth. Whisk in the flour mixture until just combined. 
  4. Scrape the batter into the prepared pan. Bake until the loaf is puffed and deeply golden, and a cake tester inserted into the center comes out clean, 45 to 50 minutes. Let the loaf cool in the pan for 10 minutes, then pull out by the parchment overhang onto a cooling rack. Let cool for another 30 minutes, or completely, before slicing in.
  5. Store leftovers in an airtight container for up to 1 week; or wrap tightly and freeze for 3 months.

Sourdough Starter Discard Lemon Poppyseed Loaf FAQs

Can I use another citrus in place of lemon?

Yes! Grapefruit, orange, or lime zest and juice would be lovely swapped in for lemon. 

Can I use Greek yogurt instead of plain whole-milk yogurt?

Yes, 57 grams (¼ cup) plain Greek yogurt (preferably full-fat) or sour cream can be swapped in for the whole-milk yogurt if that’s what you have on hand. They’ll make for a slightly more rich cake. Buttermilk can be swapped in too, but it’ll be less rich, and the cake will be slightly tangier.

Can I bake this in a 9×5-inch loaf tin?

Yes, you can use a 9×5-inch loaf tin for this cake if that’s what you have. The cake will be shorter and wider and bake on the lower end of the timing range, so start checking it for doneness at 40 minutes.

Can I use more sourdough starter discard in this recipe?

I don’t recommend adding more sourdough starter discard to this recipe. When I tried versions with a higher starter content, the cake was so tangy the flavor bordered on distracting. Further, to add more starter you’d need to omit more water via yogurt, egg, or lemon juice, which doesn’t turn out to my preference texturally (see the section above on what happens when you omit these ingredients).

Can I add icing?

Sure! Many lemon poppyseed loaf cake recipes are glazed with a lemony icing. If you’d like to make one, whisk together 57 grams (½ cup) powdered sugar with 13 grams (1 tablespoon) lemon (or whichever citrus you used in the cake) juice and a pinch of kosher salt until smooth, adding more juice by the drop as needed to thin the glaze. When the cake has cooled completely, pour the glaze over.

What’s Next?

After you’ve had your fill of this tasty lemon poppyseed loaf, see our list of sourdough starter discard recipes for more tasty treats!

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Rebecca Firkser
Rebecca Firkser is a Brooklyn-based writer, editor, recipe developer, and food stylist. Most of her work consists of translating professional cooking into content that’s digestible—figuratively and literally—to home cooks. You can find her work at Epicurious, Bon Appetit, NYT Cooking, Food52, Serious Eats, Kitchn, and TASTE, among others. She's currently working on her first cookbook, a deep-dive into galettes. Once upon a time, she studied theater design and art history at Smith College, so if you want to talk about Wayne Thiebaud's cakes, she's your girl.