Sourdough Strawberry Cake With Strawberry Buttercream

If you’re sitting on a jar of sourdough discard and a pile of juicy strawberries, this is your sign to bake the most irresistible cake of the season: sourdough strawberry cake with strawberry buttercream.

We’re talking real fresh strawberry flavor in every bite, a tender crumb thanks to that sourdough starter discard, and a frosting so dreamy you’ll want to eat it by the spoonful. This is not your average strawberry cake!

This is summer joy in layer-cake form. And I’m not just saying that.

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Every June since I was a kid, I’ve gone strawberry picking. It started with my grandparents taking me out into the fields, baskets swinging in hand, sun on our backs, and red-stained fingers by the end of the day. It was the highlight of my summer, every single year. As I got older, that tradition stayed with me. When I got married, my husband joined in. And now, with our own little crumb catchers in tow, we make it a full family event! Strawberry-sticky hands (arms and legs) and all!

We usually pick close to 50 liters (yes, liters) of ripe, juicy strawberries. Because when you go that hard for tradition, you go big. What we don’t devour fresh, we freeze for the year. Our freezer becomes this beautiful, berry-filled treasure chest we dip into all year long for smoothies, crisps, jam, and of course… cake.

And not just any cake. This cake. Moist, fruity, with that fresh strawberry flavor bursting in every bite. It’s our favorite way to celebrate strawberry season, and now, it can be yours too!

Why You’ll Love This Sourdough Strawberry Cake

• Fresh Strawberry Flavor: We reduce real strawberries into a rich purée for the cake and buttercream. No fake flavoring here!
• Moist and Tender: Thanks to sourdough discard, oil, and eggs, this cake stays ultra-soft.
• Perfect for Any Occasion: Whether it’s a summer gathering, birthday, or just a sweet treat for your family, this cake bakes up beautifully every time.
• A Delicious Way to Use Discard: Leftover sourdough discard? Use it here instead of tossing it.

Ingredients You’ll Need For Sourdough Discard Strawberry Cake

For the Strawberry Purée

• 1 ½ pounds fresh strawberries, hulled and chopped. You can use frozen strawberries too, but be sure to thaw and drain any liquid first.

For the Strawberry Sourdough Cake Batter

• all-purpose flour
• baking powder
• baking soda
• salt
• neutral oil (avocado oil, canola, or vegetable oil work well)
• granulated sugar
• eggs, room temperature
• vanilla extract
• milk (dairy or non-dairy), room temperature
• sourdough discard, room temperature. For the best flavor, use fresh sourdough discard, ideally from the same day or within a day or two. Older discard can develop a stronger tang that might compete with the sweet strawberry flavor, and we’re going for fruity, not funky!
• ½ cup reduced strawberry purée, cooled
• Optional: a drop or two of natural pink food coloring (without it, the cake may lean slightly grey)

For the Strawberry Buttercream

• unsalted butter, room temperature
• powdered sugar
• ¼ cup reduced strawberry purée, cooled
• vanilla extract
• salt

How to Make the Strawberry Reduction

This is where all that fresh strawberry flavor shines. You’ll use ½ cup of the strawberry reduction in the cake and ¼ cup in the frosting, so measure carefully!

1. Hull and quarter 1 ½ pounds of strawberries and toss them into a saucepan over medium heat. Use a potato masher to lightly mash the berries, just enough to get some juices flowing so they don’t scorch on the bottom. No need to go wild here. Alternatively, you can blend them first for a smoother consistency right from the start.

2. Bring the mixture to a gentle simmer and cook, stirring constantly, until it’s reduced to a thick paste. This usually takes 30–45 minutes, depending on your pan and heat level. You’re aiming for a thick, jammy consistency, and about ¾ – 1 cup total. The reduction will thicken up as it cools. 

3. Let it cool completely before using (pop it in the fridge to speed things up). Hot purée will mess with your cake batter and buttercream, so patience pays off here!

How to Make the Sourdough Strawberry Cake

Step 1: Prep the pans

Preheat oven to 350°F. Butter two 9-inch round cake pans (or spray with baking spray), and line the bottoms with parchment paper.

Step 2: Mix dry ingredients: 

In a large bowl, whisk together the flour, baking powder, baking soda, and salt.

Step 3: Cream the wet ingredients

In a large mixing bowl (or the bowl of a stand mixer with the paddle attachment), beat the sugar and eggs together on medium speed for 2–3 minutes, until the mixture is pale and slightly thickened. Add the vanilla and mix just until combined. With the mixer on low, add in the oil and mix until fully incorporated.

Step 4: Add the discard

Continuing with the mixer on low, mix in the sourdough discard.

Step 5: Finish the batter

Add the flour mixture in three parts, alternating with the milk and the ½ cup strawberry reduction. Mix just until combined. Don’t overmix! If desired, add a touch of pink food coloring here. The batter tends to come out looking a bit grey without the inclusion of pink food coloring. If you prefer not to use artificial dye, you can use all natural dye instead.

Step 6: Bake

Divide the batter evenly between the prepared cake pans and smooth out the tops. Bake for 28–32 minutes, or until the cakes are golden brown, spring back when gently pressed, and a toothpick inserted in the center comes out clean.

Step 7: Cool 

Let the cakes cool in the pans for 15 minutes, then carefully turn them out onto a wire rack. Peel off the parchment paper and let the cakes cool completely.

For easier decorating, pop the cooled cakes into the freezer for 30–60 minutes before frosting. This helps firm them up and makes applying a crumb coat a whole lot smoother.

Making the Strawberry Buttercream

1. In a large bowl (using a hand mixer or the whisk attachment of a stand mixer), beat the softened butter, 1 cup powdered sugar, vanilla, and salt until smooth and creamy.

2. Gradually add the remaining powdered sugar, beating on low and increasing to medium speed as the frosting thickens. Cover with a clean tea towel if needed to avoid a powdered sugar snowstorm!

3. Add the cooled strawberry purée and mix just until smooth and combined. Scrape down the bowl and mix briefly once more. Don’t overbeat, the buttercream should be silky and hold soft peaks.

Tips for Assembling Your Sourdough Strawberry Cake

Once your cakes have chilled in the freezer for 30–60 minutes, you’re ready to assemble! Chilling the layers helps reduce crumbs and makes the decorating process much smoother, especially if you’re going for that dreamy, clean finish.

Step 1: Level the Layers (Only If Needed)

If your cake layers domed a bit during baking, now’s the time to gently level them. Use a serrated knife to carefully trim just the tops so they sit flat. That said, only cut them if you have to. The more you trim, the harder it can be to get smooth, even buttercream coverage. If they’re close enough to flat, roll with it!

Step 2: Start with Your First Layer

Place one cake layer on a lazy susan, cake stand, or serving plate.

Then, spread a generous layer of strawberry buttercream over the top. This is your middle filling, so go for thick and even. Aim for about ½ – ¾ cup.

Next add your second cake layer on top.

Step 3: Crumb Coat for a Clean Finish (Optional but Recommended!)

If you’re aiming for that sleek, bakery-style look, a crumb coat is your best friend!

• Apply a thin layer of buttercream all over the top and sides of the cake, just enough to trap crumbs.
• Don’t worry if it looks a little messy. This layer gets covered up. I use my bench scraper to smooth this layer out.

• Then, apply the remaining buttercream to finish frosting. Use a bench scraper or offset spatula to smooth the sides and top. This makes things easier if you’re new to cake decorating or just want a tidy look without going full perfectionist.

Step 4: Top it Off (If desired)

Add a handful of fresh berries on top for a beautiful (and simple) finish. That’s really all you need! This strawberry buttercream already steals the show!

How to Store Your Sourdough Strawberry Cake

Because this cake features a fresh strawberry reduction in both the batter and buttercream, it’s important to keep it fresh and safe to eat.

• Room Temperature: This cake should not be left out for more than 2 hours at room temperature to avoid spoilage.
• Refrigeration: Store leftovers in an airtight container in the fridge. This will keep your cake fresh for up to 3–4 days.

Did you try this recipe? I’d love to see how it turned out! Leave a comment below and tag @catchthecrumbsourdough on Instagram to show it off!