Chocolate Zucchini Sourdough Muffins with Cocoa Swirl

Rich Chocolate Sourdough Zucchini Muffins are a chocolate lover’s new go-to. Packed with finely shredded zucchini — no wringing required — and sourdough discard, these muffins stay moist and tender. They remind me of my sourdough chocolate cupcakes and zucchini cake, and they’re a delicious way to use summer zucchini. My kids adore them, and they’re a simple, family-friendly bake.

Why You’ll Love Chocolate Sourdough Zucchini Muffins

• Moist and tender: Finely shredded zucchini gives these muffins a soft, cake-like texture while staying hidden in the batter.
• Veggie-packed: You get a generous amount of zucchini without losing the chocolate flavor — a great balance of indulgence and nutrition.
• Quick and simple: The batter comes together in minutes with straightforward ingredients and minimal technique.

Important Ingredients

• Sourdough discard – About 100 g (scant 1/2 cup). I use 100% hydration discard. Older discard will add more tang; use fresher discard for a milder flavor.
• Unsalted butter – Melted; I use unsalted so I can control the salt level.
• Vegetable oil – Combined with butter for extra tenderness and moisture.
• Sugar – Granulated sugar for sweetness.
• Egg – One large egg for richness and structure.
• Milk – 2% or whole milk works best.
• Vanilla extract – Enhances the overall flavor.
• All-purpose flour – Regular or lower-protein pastry flour are fine.
• Cocoa powder – Use a good-quality dutch-processed or natural cocoa depending on your preference.
• Baking soda & baking powder – Both are used to ensure a good rise.
• Salt – Balances and enhances the chocolate flavor.
• Zucchini – Finely shredded zucchini keeps the muffins moist; no squeezing required.
• Chocolate chips – Optional, for extra chocolate pockets.

How to Make Chocolate Sourdough Zucchini Muffins

Prepare the Batter

Start by mixing the wet ingredients in a small bowl: sourdough discard, melted butter, vegetable oil, and sugar. Make sure the butter is warm but not hot, then whisk until combined. Add the egg, milk, and vanilla and whisk again until smooth.

In a large bowl, whisk together the dry ingredients: all-purpose flour, cocoa powder, baking powder, baking soda, and salt. Set aside.

Add Zucchini and Mix

Wash the zucchini, trim the ends, and finely shred it using the small side of a box grater. Fine shreds blend into the batter so the muffins stay moist without visible green strands. There’s no need to drain or squeeze the zucchini for this recipe.

Pour the wet mixture over the dry ingredients and gently stir until partially combined. Fold in the shredded zucchini and chocolate chips, stirring just until the batter comes together — a few dry streaks are fine. Overmixing will make the muffins tough.

Bake the Muffins

Preheat the oven to 425ºF. Line a 12-cup muffin tin with parchment or paper liners, or lightly grease the cups if you prefer not to use liners. Divide the batter, about 1/3 cup per well, which yields roughly 12 muffins.

Bake at 425ºF for 5 minutes, then reduce the oven temperature to 350ºF and continue baking for 12–15 minutes. Test for doneness by inserting a toothpick in the center; some streaks of melted chocolate are fine, but there should be no wet batter on the pick. If needed, bake a few more minutes and test again.

Allow the muffins to cool in the pan for about 5 minutes before transferring them to a wire rack to finish cooling.

Substitutions

• Sourdough starter: Use a ripe, active starter instead of discard if preferred.
• Vegetable oil: Any neutral oil works, or use all melted butter for a richer flavor.
• Chocolate: Swap semi-sweet chips for milk, dark, or chocolate chunks to suit your taste.

Sourdough Muffin Recipes

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