Sourdough Lemon Poppyseed Muffins are tender and citrus-forward, made by rubbing lemon zest into sugar to release its oils and boost flavor. A blend of butter and oil keeps them rich yet light, while a tangy glaze adds a final pop of brightness.
Preheat oven to 375°F. Line a standard 12-cup muffin pan with paper liners and lightly grease the papers.
In a large bowl, combine the sugar and lemon zest. Use your fingertips to rub them together until the sugar is fragrant and slightly damp from the zest’s oils. For best results, use a microplane zester. Its ultra-fine grating releases the oils more effectively than coarser zesters, which can leave the zest too chunky.
To the lemon-sugar mixture, stir in the eggs and sourdough discard until smooth. Whisk in the oil, vanilla, and lemon juice until fully combined.
Place a sifter over the bowl and add the flour, baking powder, baking soda, and salt. Sift directly into the wet mixture.
Remove the sifter, add the poppy seeds, and gently fold everything together until just combined. Don’t overmix. If you'd like to ferment the batter for extra flavor, cover the bowl and refrigerate it for 2 to 4 hours. Otherwise, proceed straight to the next step and get them in the oven.
Divide the batter evenly between the muffin cups, filling them ¾ full. Bake for 16–22 minutes, or until a toothpick inserted into the center comes out clean.
Let the muffins cool in the pan for 5 minutes, then transfer to a wire rack.
Make the Glaze
While the muffins cool, whisk together the powdered sugar, lemon juice, and optional zest until smooth. Adjust consistency as desired (extra lemon juice to make it thinner or more powdered sugar to make it thicker).
Once muffins are slightly warm, drizzle the lemon glaze over the tops. Let set before serving.
Notes
Sourdough Discard: Avoid sourdough discard that smells overly sour or alcoholic, which can mask the lemon flavor.Zesting Tip: A microplane zester creates very fine zest that blends easily into the sugar and releases the oils better than coarse zesters. Flour Adjustment: The batter should be thick but scoopable. If your discard is especially runny, you can add 1–2 tablespoons more flour as needed.Don’t Overmix: Overmixing will make the muffins tough or dense.Glaze Timing: Glaze while muffins are still slightly warm for better absorption and more lemon flavor throughout the muffin.Zest Before You Juice: Always zest the lemons before juicing them. It’s much easier to remove the zest from a whole lemon than from one that’s already been squeezed flat.Storage: Store muffins in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days. They also freeze well.