Blueberry Lemon Sourdough Skillet

There's something almost magical about pulling a cast iron skillet out of the oven and watching the steam rise off a golden cake studded with blueberries. This sourdough lemon skillet cake came together on a lazy Sunday afternoon when I had leftover sourdough discard sitting in the fridge and a pint of fresh berries from the farmers market. The combination felt risky at first—could tangy starter really work in a dessert?—but the moment I tasted that first warm slice, all doubt dissolved into pure citrus-butter bliss.

I made this for my neighbor Sarah one morning, still warm from the oven with the icing barely set. She showed up on my doorstep five minutes later asking if I'd baked it myself, and when I nodded, she actually laughed—the kind of delighted laugh that meant she already knew this cake was going to ruin her for store-bought desserts. We ate half of it standing in my kitchen with coffee, talking about the farmers market and the strange weather, and somehow the cake became less about the recipe and more about that particular moment.

Ingredients

• All-purpose flour: A cup gives you structure without heaviness; don't sift unless you've accidentally packed it down in storage.
• Unsalted butter: Softened is non-negotiable here; it creams into the sugar far more easily than cold butter, creating that light, fluffy base that makes the cake tender.
• Granulated sugar: Three-quarters cup sweetens the cake while keeping it moist; too much sugar makes the edges crispy and tough.
• Large eggs: Room temperature eggs emulsify better and add lift; cold eggs from the fridge will seize the batter slightly.
• Active sourdough starter: Use your discard or unfed starter; this is where the magic happens, adding depth and a gentle tang that brightens the lemon.
• Whole milk: The dairy keeps everything tender and carries flavor; don't skip this for water.
• Vanilla extract: One teaspoon rounds out the flavors without screaming vanilla; pure extract tastes cleaner than imitation.
• Lemon zest and juice: Fresh lemons only; bottled juice tastes bitter and metallic by comparison, and zest should be microplaned fine for even distribution.
• Baking powder and baking soda: Together they create a gentle rise that keeps the cake light without puffing up too much in the center.
• Fresh blueberries: The stars of the show; frozen berries work if you don't thaw them, though fresh ones have a delicate flavor that frozen can't quite match.
• Powdered sugar: For the icing drizzle; sift it first if it's lumpy so the glaze stays silky smooth.

Instructions

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Heat and prepare your vessel:

Preheat the oven to 350°F and grease a 10-inch oven-safe skillet generously. Cast iron is ideal because it holds heat evenly and creates that beautiful golden crust, but any oven-safe skillet works.

Mix your dry ingredients:

Whisk together flour, baking powder, baking soda, and salt in a medium bowl. This ensures the leavening agents are evenly distributed and prevents lumps.

Cream butter and sugar:

Beat softened butter and sugar together until the mixture looks pale, fluffy, and almost mousse-like—this usually takes three to four minutes with an electric mixer. This step aerates the batter and creates a tender crumb.

Add eggs one at a time:

Crack eggs into the mixture individually, beating well after each addition. Rushing this step results in a grainy, broken batter that won't rise properly.

Layer in the wet and aromatic elements:

Stir in vanilla, lemon zest, and fresh lemon juice, then fold in the sourdough starter gently. The starter might look lumpy at first, but it will incorporate as you mix.

Combine wet and dry gently:

Add half the flour mixture and stir until just barely combined, then pour in the milk, and finish with the remaining flour. Overmixing at this stage develops gluten and makes the cake tough.

Fold in the blueberries with care:

Use a spatula to gently fold in the blueberries, preserving their shape and preventing them from bruising and bleeding into the batter. A few streaks of purple are fine and actually look beautiful.

Fill your skillet and bake:

Pour the batter into the prepared skillet and smooth the top gently. Sprinkle a few extra berries on top if you like the visual drama, then bake for thirty to thirty-five minutes until the top is deep golden and a toothpick inserted in the center comes out clean or with just a few moist crumbs.

Cool before frosting:

Let the cake rest in the skillet for fifteen minutes—this allows the crumb to set enough to handle. Meanwhile, whisk powdered sugar with lemon juice (start with one tablespoon and add more until you reach drizzle consistency), then pour it over the cake in thin, decorative lines.

Save

This cake taught me something unexpected: you don't need fancy ingredients or complicated techniques to create something that tastes like you spent hours on it. My sister brought this to a potluck last month, and three different people asked for the recipe—the sourdough detail seemed to mesmerize everyone, as if I'd discovered some secret baker's code. In reality, it's just a way of using what you already have while making something even better.

Why Cast Iron Changes Everything

A cast iron skillet doesn't just cook food; it conducts heat so evenly that the edges of this cake brown beautifully without the center drying out. I learned this the hard way using a regular cake pan once, which resulted in a golden ring around a pale middle. Cast iron also keeps the cake warmer longer, so you get those few perfect minutes of eating it straight from the oven when the icing is just starting to set and the crumb is still steaming. If you don't have cast iron, use a ceramic or glass skillet and reduce the oven temperature by twenty-five degrees to prevent over-browning.

The Secret of Sourdough in Sweets

Most people think sourdough belongs only in bread, but a small amount of starter in cake or quick breads adds a complexity that's hard to describe and impossible to replicate with other ingredients. The fermentation process breaks down some of the starches and proteins, making the cake easier to digest and adding subtle notes that balance sweet flavors. It's like adding a whisper of salt to chocolate—you don't taste the salt, but you taste how much better the chocolate becomes.

Lemon as a Bridge Flavor

Fresh lemon does something remarkable in baked goods: it brightens everything without making anything taste sour or citrusy. The acid reacts with the baking soda and baking powder, contributing to the rise while also cutting through the richness of butter and eggs. I've noticed that cakes made with both zest and juice taste more rounded and sophisticated than those made with just one; the zest provides aroma and essential oils while the juice adds tartness that plays beautifully against the blueberries and sourdough.

• Microplane your lemon zest directly over the mixing bowl so you capture all those fragrant oils.
• Squeeze your lemons fresh on the morning you bake; bottled juice begins oxidizing the moment it's pressed.
• If you accidentally add too much zest, don't panic—a little extra just makes the cake more assertively lemony, which some people actually prefer.

Mix doughs, batters, and whipped cream easily for baking cakes, cookies, and everyday treats.

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Save

Make this cake when you have sourdough discard burning a hole in your conscience and fresh berries calling to you from the farmer's market. Slice it warm, drizzle it with cold icing, and watch how something this simple becomes the thing people remember about your kitchen.

Recipe FAQ

→ What type of blueberries work best for this cake?

Fresh blueberries are ideal for a burst of flavor, but frozen can be used directly without thawing to maintain texture and prevent bleeding.

→ How does the sourdough starter affect the cake?

The sourdough starter adds a subtle tang and depth, improving moisture and complexity in the cake's flavor profile.

→ Can I substitute lemon with other citrus?

Yes, orange zest and juice make a delicious alternative, offering a sweeter citrus twist to the cake.

→ What skillet is recommended for baking?

A 10-inch cast iron skillet is preferred for even heat distribution and the best skillet cake texture.

→ How should I store leftovers?

Store cooled cake in an airtight container at room temperature for up to two days or refrigerate for longer freshness.