Sourdough Brown Butter Zucchini Bread

Summer is here- and that means our gardens are bursting with fresh zucchini. Zucchini is such a versatile squash- it can be used in lasagna, stews, sides but I think my very favorite way to use zucchini is to bake with it! This Sourdough Brown Butter Zucchini Bread is everything you want in zucchini bread and a little more. Brown butter brings a caramelized flavor to this loaf and sourdough discard is used to ferment the batter to make it easy on the belly. This bread has all the nostalgia of Grandma's zucchini bread with a baker's twist to really elevate it!

Why You’ll Love This Recipe

This recipe uses simple ingredients and can be whipped up quickly. Brown butter brings a nutty richness that perfectly balances the sweetness of brown sugar , while the zucchini and sour cream melts into this loaf adding moisture and flavor. Customize this batter to fit your needs and schedule by fermenting overnight, or you can mix and bake in under an hour. Either way, the results are delicious!

Why Use Sourdough in this Sourdough Brown Butter Zucchini Loaf?

Using sourdough discard in this brown butter zucchini adds a slight tang, enhances moisture retention, and makes the crumb softer and more tender. The fermentation process also helps break down gluten, making this loaf easier to digest.

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Tools You’ll Need:

• Hand mixer or sturdy whisk- for blending batter.

• Mixing bowls- (1 large, 1 medium)- to mix batter and dry ingredients.

• Whisk and spatula- to combine ingredients and spread batter in pan.

• Cheese or veggie grater- for grating zucchini. You can also use a food processor.

• 9x5-inch loaf pan- to bake your loaf. I love these pans from USA linked here https://amzn.to/3SrVIC6.

• Parchment paper- to line your pan to avoid burning.

• Paper towels- to dry zucchini.

• Kitchen scale (optional)- for accurate measuring—especially helpful with sourdough baking.

• Wire cooling rack- to cool your loaf.

Next, Gather Your Ingredients:

Fresh Zucchini- Brings natural sweetness, moisture, and tenderness to the bread. It's the secret to that soft, bakery-style texture that stays fresh for days.

Unsalted Butter- browned to bring a rich caramel taste and enhances flavors of the zucchini.

Sour cream- Adds moisture and tang to balance sweetness and enhance richness.

Brown sugar- Provides caramel depth and chew.

White sugar- Boosts sweetness and supports the rise and golden color.

Honey- Boosts sweetness and gives loaf a light floral note that balances the earthiness of the zucchini.

Vanilla extract- Enhances the flavor and brings warmth.

Sourdough starter- (flat or past peak, can be cold or room temperature). Adds depth of flavor, moisture, and just a whisper of tang—without making this bread "sour". Key for fermentation.

Eggs (room temperature)- provide structure and lift with moisture, works as a binder for ingredients.

All-purpose flour- Gives the bread structure while keeping it soft and cakey.

Baking powder + Baking soda- Ensures the right rise and tenderness.

Salt- Balances sweetness and enhances all the other flavors.

Cinnamon, Ginger, and Cardamom- These spices round out the zucchini flavor with cozy, aromatic warmth.

Chopped walnuts or pecans (Optional)- Adds texture and a nutty complement to the bread.

Semi-sweet Chocolate Chips (Optional)- Adds pockets of gooey chocolate to the bread. Compliments the zucchini and brown butter well.

Now, let's bake!

Sourdough Brown Butter Zucchini Bread

Wet Ingredients:

• 1½ cups finely shredded zucchini, before draining (180g)

• 6 tbsp unsalted butter, browned (85g)

• ¼ cup sour cream (60g)

• ⅓ cup packed brown sugar (75g)

• 1 tbsp honey (20g)

• ⅓ cup granulated sugar (70g)

• 1½ tsp vanilla extract

• ⅓ cup sourdough starter (80g)

• 2 large eggs

Dry Ingredients:

• 1⅔ cups all-purpose flour (200g)

• 2 tsp baking powder

• ½ tsp baking soda

• ½ tsp salt

• 1½ tsp cinnamon

• ¼ tsp ground ginger

• Pinch (⅛ tsp) ground cardamom

Optional Mix-Ins:

• ½ cup chopped walnuts or pecans (50–60g)

• ½ cup chocolate chips (90g)

Instructions:

Brown the Butter:

In a medium saucepan, melt the butter over low heat. Continue cooking, stirring frequently, until the butter foams and turns a rich amber color with brown specks at the bottom, emitting a nutty aroma. Remove from heat immediately. This process typically takes about 5-7 minutes.

Once butter is browned, remove the saucepan from heat and transfer the bowl you'll be using to mix your batter.

Grate Zucchini:

Grate fresh zucchini until you have roughly 1 1/2 cups (180g). Lay out a paper towel and spread zucchini over paper towel in a thin layer. Sprinkle 1 teaspoon sea salt all over the zucchini. This process is called "sweating" and will help remove some of the moisture. Let zucchini rest for 10 minutes.

After ten minute rest pat with paper towels or a lint-free kitchen towel to remove excess moisture. Transfer shredded zucchini to a bowl and set aside. If you choose to do an overnight fermentation, you can save this step for the morning you wish to bake your loaf.

Mix Batter:

In the bowl you poured your brown butter, add the sour cream and whisk to gently cool off the butter before adding the rest of your wet ingredients. Add brown sugar, white sugar, honey, vanilla, sourdough starter, and eggs to the bowl.

Beat wet ingredients with a whisk or a hand mixer until everything is well combined.

In a separate bowl, combine flour, salt, baking soda, baking powder, cinnamon, ginger, and cardamom. Whisk to combine dry ingredients.

Add dry ingredients to wet, and gently mix to combine. You don't want any streaks of flour, but be careful not to overmix at the same time. At this point, you can decide to do an overnight ferment option or skip the next step and bake same-day.

Overnight ferment option: 

Cover batter with plastic and refrigerate overnight. Remove bowl from refrigerator and allow to rest 30 minutes at room temperature. While batter is warming, prepare your zucchini as listed above.

Fold shredded zucchini and any other mix-in's you would like into your batter.

Bake the Zucchini Bread:

Preheat oven to 350°F (175°C). Grease and line a 9x5-inch loaf pan with parchment paper.

Pour batter into pan, smooth the top, and make a line with your spatula down the center to guide the expansion. Bake 50–60 minutes, or until a toothpick comes out clean.

Batter should only fill pan 2/3 of the way full- more than this could lead to spillage. I like to place a cookie sheet on the rack beneath my bread to avoid any messy ovens. Loaf internal temperature should be 200-205 F when done. Cool in pan 10 minutes, then transfer to a rack. Allow to cool 30 minutes before slicing.

Enjoy your fresh Sourdough Brown Butter Zucchini Bread!

Yields 1 loaf

How to Store:

Room Temperature

• Store the fully cooled loaf tightly wrapped or in an airtight container at room temp for up to 3 days.

• For best texture, wrap in parchment or wax paper first, then place in a resealable bag or container to prevent sogginess.

Refrigerator

• If your kitchen is humid or you want to extend shelf life, refrigerate in an airtight container for up to 1 week.

• Let slices come to room temp or warm slightly before serving for the best flavor and texture.

Freezer

• Slice the fully cooled loaf and wrap individual pieces in parchment paper or plastic wrap.

• Place wrapped slices in a freezer-safe bag and freeze for up to 2 months.

• To reheat, thaw at room temperature or warm briefly in a toaster oven or microwave.

FAQ'S:

Can I skip the overnight ferment?

Absolutely — just bake right after mixing in the zucchini for a delicious quick version.

Can I use discard straight from the fridge?

Yes! Flat, unfed starter is perfect for this recipe.

Do I have to sweat the zucchini?

It’s highly recommended. If you skip it, the loaf may be overly wet or sink in the center.

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