Sourdough Discard Zucchini Bread
This sourdough discard zucchini bread is the perfect way to use up leftover starter. It's deeply moist, warmly spiced with cinnamon and nutmeg, and packed with freshly grated zucchini for an incredibly tender crumb. The subtle tang from the discard rounds out the sweetness beautifully and helps the loaf stay fresh longer than a standard quick bread.
Equipment
- 9x5-inch loaf pan - 23x13cm
- Large mixing bowl
- Medium mixing bowl
- Box grater
- Clean kitchen towel or cheesecloth - for squeezing zucchini
- Whisk
- Rubber spatula or wooden spoon
- Digital kitchen scale - recommended for accuracy
- Measuring cups and spoons
- Wire cooling rack
- Toothpick or cake tester
Ingredients
- 1 ½ cups all-purpose flour - 190g
- ½ tsp baking soda
- 1 tsp baking powder
- ½ tsp fine salt
- 1 tsp ground cinnamon
- ¼ tsp ground nutmeg
- ¾ cup granulated sugar - 150g
- ¼ cup packed brown sugar - 50g
- 2 large eggs - room temperature
- ½ cup neutral vegetable oil - 120ml; or melted coconut oil
- ½ cup sourdough discard - 120g; 100% hydration, unfed
- 1 tsp pure vanilla extract
- 1 ½ cups freshly grated zucchini - about 200g, excess moisture squeezed out
- ½ cup chopped walnuts - 60g; optional but highly recommended
Optional Add-ins
- ½ cup semi-sweet chocolate chips - 85g; optional
- ¼ cup golden raisins - optional
- 1 lemon zest - from one large lemon; optional for lemon variation
- 1 tbsp lemon juice - optional for lemon variation
- coarse sugar - for sprinkling on top, optional
- softened salted butter - for serving
- cream cheese - for serving
- honey - for serving
Instructions
- Preheat oven to 350°F (175°C). Grease a 9x5 inch loaf pan and line with parchment paper leaving an overhang.
- Grate zucchini using the large holes of a box grater. Squeeze firmly in a clean towel to remove excess moisture, then set aside.
- In a medium bowl, whisk together flour, baking soda, baking powder, salt, cinnamon, and nutmeg until evenly combined.
- In a large bowl, whisk granulated sugar, brown sugar, and eggs until lighter in color. Add oil, sourdough discard, and vanilla, whisking until smooth.
- Add dry ingredients to wet and fold gently with a spatula until just combined—do not overmix. Fold in squeezed zucchini and any optional mix-ins.
- Pour batter into the prepared pan and smooth the top. Sprinkle with coarse sugar if desired. Bake for 55 to 65 minutes until a toothpick comes out clean.
- Cool in pan on a wire rack for 15 minutes, then lift out using parchment handles. Cool completely for at least 30 to 45 minutes before slicing.
Notes
- Squeeze the zucchini well: This is the most important step. Excess moisture will make the bread soggy and undercooked in the center. Squeeze until the zucchini feels significantly drier.
- Use room temperature eggs: Cold eggs can cause the oil to seize. Place eggs in warm water for 5 minutes if you forgot to take them out ahead.
- Don't overmix: Stir gently and stop as soon as the batter comes together. Overmixing activates gluten and results in a tough, rubbery crumb.
- Fresh discard works best: Discard that's a few days old gives the best flavor. Very old discard can add too much acidity and affect the rise.
- Test for doneness: Insert a toothpick into the very center. It should come out clean or with a few moist crumbs—not wet batter.
- Let it cool completely: The interior keeps cooking from residual heat even after leaving the oven. Full cooling prevents a gummy texture.
- Whole wheat variation: Replace up to half the all-purpose flour with whole wheat flour for a denser, more nutritious loaf with a nutty flavor.
- Storage: Wrap tightly and store at room temperature for 3 to 4 days, refrigerate for up to 7 days, or freeze for up to 3 months.
- Make it your own: Add chocolate chips, walnuts, raisins, or try a lemon variation by omitting cinnamon and nutmeg and adding lemon zest and juice.
- This bread gets better: The flavors meld together overnight, making it ideal for baking a day ahead.