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5 from 2 votes

Rustic Zucchini and Walnut Sourdough Bread Recipe

This moist, fluffy, chewy zucchini sourdough bread is a healthy and savory twist on traditional zucchini bread. It is the perfect way to use up some of your excess homegrown zucchini, or simply inject more veggies into your life – which is always a good thing! It’s also much more versatile than sweet zucchini bread, and can easily be enjoyed on its own, as sandwich bread, or as a side with other meals.
Prep Time30 mins
Cook Time45 mins
Ferment & Proofing Time16 hrs
Servings: 1 loaf of bread


  • Large mixing bowl
  • Lined banneton bread basket, for shaping and proofing dough
  • Kitchen scale
  • Cast iron combo cooker or dutch oven
  • Grater, to shred zucchini
  • Colander or strainer
  • Bread lame for scoring (optional)


  • 120 grams active sourdough starter
  • 455 grams total flour - we use 295 grams of white bread flour, 140 grams of whole wheat, and 20 grams of rye flour
  • 1.25 cups filtered water in very humid climates, start with 1 cup of water and add more as needed
  • 9 grams salt - sea salt, kosher salt, or Himalayan salt is preferred over iodized table salt (plus a sprinkle on the zucchini)
  • 1 medium zucchini, grated (approximately 1 to 1.5 cups, see sliding scale notes below)
  • 1/2 cup walnuts - we use raw, unsalted, halves & pieces substitute with unsalted sunflower seeds or pumpkin seeds for those with walnut allergies
  • optional: ½ tsp of garlic powder and 2 tsp of onion powder


  • Before making the dough, be sure to feed your sourdough starter at least twice, allowing it to reach peak activity level.
  • Make an autolyse by combining the flour and water in a bowl until thoroughly mixed. Let it sit covered at room temperature (70-75 degrees is optimal) for about an hour. (The dough may seem more dry than usual sourdough, because the zucchini will add more moisture soon)
  • While the autolyse is resting, prepare the zucchini - which also needs to sit and rest after grating. Use a box grater to shred one medium zucchini into a colander or strainer. Next, sprinkle the zucchini with a few light shakes of salt, and toss to mix. Rest the strainer in a very clean sink, or set it over a larger bowl. Over the next 15 to 30 minutes, the salt will draw excess water out of the zucchini. Toss and lightly press (wring out) the zucchini a few times while you wait - about 5 to 10 minutes apart. Do not add the collected zucchini water to the recipe!
  • After the autolyse has rested for nearly an hour, mix in the called-for active sourdough starter, salt, and grated drained zucchini until thoroughly combined. Mixing with your hands is normal and acceptable. (Also add optional ½ tsp of garlic powder and 2 tsp of onion powder).
  • Optional: Lift the dough ball (which may be quite loose) out of bowl and on a clean counter use the “slap and fold” technique to tighten the dough.
  • Once finished, put the dough back in the bowl and allow to rest at room temperature for 30 minutes. Cover the bowl with a damp tea towel or similar. This begins the "bulk fermentation" time.
  • After 30 minutes, add the walnuts and then start the first round of “stretch and fold” - gently lifting up on one side of the dough and folding it back over itself. Give the bowl a quarter turn and continue to stretch and fold the dough until it is taught and resists pulling. Avoid tearing the dough. Use wet hands to prevent sticking. Cover the bowl again, and let sit.
  • Repeat the stretch and fold process every 30 minutes for a total of 3 or 4 rounds.
  • After about 4 hours of bulk fermentation at room temperature, stretch and fold the dough one final time to help it tighten up.
  • Next, set the dough on a lightly floured surface and shape the loaf into a similar shape as your banneton (proofing basket - e.g. a round loaf, or long oval loaf). Let the dough “bench rest” for a final 10 minutes.
  • After the final bench rest, place the dough in a flour-dusted (and potentially cloth-lined) banneton proofing basket of choice. Cover with a breathable towel, and place in the refrigerator to proof for 8 to 16 hours. We usually do this overnight.
  • After cold-proofing in the refrigerator, preheat the oven to 475 to 500 degrees F. (Experiment to see what temperature works best for your oven). If you’re using a dutch oven or combo cooker, place it in the oven to preheat for one hour.
  • After an hour of preheating, quickly and carefully transfer the cold dough (straight from the fridge) out of the banneton and into the hot combo cooker or dutch oven. Line the combo cooker or dutch oven with parchment paper first. Score the top of the loaf with a bread lame if desired. (See Note 1 below)
  • Bake the loaf covered for approximately 40 minutes, and then remove the lid and bake for an additional 5 minutes uncovered. (See Note 2 and Note 3 below)
  • Once done, immediately remove the finished sourdough loaf from the oven and combo cooker and place the loaf on a wire rack to cool.
  • Let the sourdough bread loaf sit at room temperature for several hours before cutting. The steam trapped inside is important moisture to retain!
  • Enjoy!
  • To store your bread, I suggest wrapping it in a lint-free tea towel before putting it inside a paper bag. That way, you can enjoy it over four to five days. However, if it becomes stale, you could also toast or broil it first!


  1. To transfer the dough from the banneton to the hot combo cooker or dutch oven, try this trick: Place a piece of parchment paper (cut to just larger than the banneton and loaf) on top of the banneton and exposed dough. Then place a cutting board on top. Holding both the cutting board and banneton, flip the whole thing over. Lift the banneton away, leaving the dough ball sitting on the parchment paper and cutting board. Carefully slide the parchment paper into the combo cooker or dutch oven. 
  2. Baking times may vary slightly depending on your oven. Lately we've been doing 37 minutes covered and 5 minutes uncovered.
  3. If the bottom of your loaf seems to brown more than you'd like, try adding an empty baking or cookie sheet to the empty oven rack directly below your combo cooker or dutch oven. It deflects some of the heat away from the bottom of the loaf, reducing burning or browning. 
  4. To double this recipe, double all ingredients and follow the same steps until it is time to form the loaf and bench rest. At that time, split the larger dough into two equal balls. Form each loaf and allow each to bench rest, and then proceed with the instructions using two proofing baskets. Keep the spare loaf refrigerated while the other is baking, unless you have the ability to bake them at the same time.