Sourdough Zucchini Slice

Soft, savory, and never soggy thanks to my exact zucchini draining method, this easy sourdough discard recipe—made with fresh zucchini, eggs, cheese and savory fillings—is ideal for elevated meal prep, lunchboxes, and parties.

Zucchini “slice” is hard to wrap your head around if you’ve never tried it before.

It’s a classic, well-loved Aussie bake: part frittata, part savory quick bread, featuring fresh grated zucchini as the star ingredient.

My sourdough version emerged from the depths of my recipe riddled brain with the intent of tackling two common problems: what to do with sourdough discard and a seasonal zucchini surplus.

Soft, but never soggy, my sourdough zucchini slice is the latest original sourdough discard recipe to come out of my kitchen with a generous pour of olive oil, naturally fermented starter (active or discard is fine), and a sprinkle of onion-y chives for a signature twist.

Sourdough zucchini slice made with sourdough discard, grated zucchini, cheddar cheese, ham, chives and eggs, cut into squares and stacked on a parchment-lined, wooden cutting board.

Sourdough zucchini slice ingredients on a wooden cutting board — Grab your ingredients

Grated zucchini in a kitchen towel — Grab your ingredients

How To Make Sourdough Zucchini Slice (Step-By-Step Recipe)

Step 1: Prep Your Zucchini

To Start: You’ll preheat your oven (350 F) and line an 8×8-inch pan with parchment paper. I like to grease my pan first, so the paper sticks down nicely and it doesn’t crumple up in the corners. Use this time to prep the zucchini. See below.

How To Avoid Mushy Zucchini Slice:

Watery, moisture-locked zucchini is notorious for creating soggy zucchini slice (same goes for zucchini bread). Here’s my tips to fix it:

Use a box grater to grate the zucchini
Squeeze well in a clean dish towel to drain excess water (don’t skip this step).
Always weigh your zucchini after draining it. This is key. For this recipe, you’ll need about 170-180g for best texture. I’ve been using this kitchen scale since culinary school!

A spoonful of sourdough starter added to a large mixing bowl with whisked eggs — Add sourdough starter to the eggs

Olive oil added to mixing bowl with whisked eggs and sourdough starter — Add sourdough starter to the eggs

Step 2: Make The Batter

Next: Whisk your eggs in a large bowl. Then add sourdough starter (you’ll only need 50 g) and olive oil. Please don’t be tempted to add more sourdough starter for whatever reason. The extra water will throw off the ingredient ratios and make the texture rubbery. Add the flour and baking powder and mix until lump-free.

Tip: The batter should be pourable, but not runny or loose. Texture will vary based on the hydration % of your sourdough starter. My starter is 100% hydration (equal parts flour and water by weight) fed with bread flour.

Sourdough zucchini slice batter with fillings: grated zucchini, ham, cheddar cheese, chives, eggs, salt and pepper — Add the fillings

Sourdough zucchini slice batter — Add the fillings

Step 3: Add Fillings

Fold in the grated and drained zucchini, onions, cheddar cheese, ham and chives. Sprinkle with salt and pepper. I like to reserve a bit more of the fillings to sprinkle over the top for decoration (I do this by eye). Smoked ham or even Italian Parmacotto is excellent in this dish. I use white cheddar, not orange.

Step 4: Bake

Your sourdough zucchini slice should take about 35-40+ minutes in the oven, or until it’s perfectly golden brown and the surface is set. Do not underbake. Once completely cool, cut into slices.

Sourdough zucchini slice made with sourdough discard, grated zucchini, cheddar cheese, ham, chives and eggs, baked and cut into squares on a parchment-lined, wooden cutting board.

Photography & Styling by Saltwater Studio.

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Author: Emilie Raffa
Prep Time: 10 minutes
Cook Time: 40 minutes
Total Time: 50 minutes
Yield: 16 squares 1x
Category: Sourdough Discard Recipes
Method: Oven-Baked

Description

This easy sourdough discard recipe is packed with zucchini, eggs, cheese, and savory fillings like onion and ham. Soft, flavorful, and never soggy thanks to my exact zucchini-draining method, it’s perfect cut into squares for meal prep, lunchboxes, parties. Enjoy warm or at room temperature.

5 large eggs
50g sourdough starter (active or discard)
90g (about 1/2 cup) light olive oil
100 g all-purpose flour
2 tsp baking powder
2 medium zucchini (appx. 250g), trimmed, grated and drained-well to weigh 170-180g
75g diced onion
75 g diced deli ham (Italian ham or smoked ham)
75g grated white cheddar cheese
2 tbsp. minced chives
Salt & freshly ground black pepper, to taste

For garnish:
Extra grated zucchini, ham, and 1 tbsp. minced chives

Instructions

Preheat oven to 350°F. Grease and line an 8×8-inch square baking pan with parchment paper (flat sides with overhang, not crumpled in the corners).
In a large bowl: whisk the eggs.
Whisk in the sourdough starter, followed by the olive oil.
Add flour and baking powder; mix until smooth and lump-free.
Fold in grated zucchini, onion, ham, cheddar cheese and chives. Season with a pinch of salt and pepper.
Pour mixture into prepared pan and smooth the top. Evenly sprinkle some extra grated zucchini, ham, and chives over the top for decoration.
Bake for 35–40+ minutes, or until the top is golden brown, the center is set when lightly pressed, and a toothpick inserted into the middle comes out clean.
Let cool in the pan for 10 minutes. Use the parchment overhang to lift up the zucchini slice; transfer to a wire rack to finish cooling.
Cut into 16 squares, to serve.