Long-Fermented Sourdough Blueberry Lemon Streusel Muffins

There’s something magical about the slow fermentation process—how time transforms simple ingredients into something richer, more flavorful, and irresistibly tender. These long-fermented sourdough lemon blueberry streusel muffins are the perfect example of that magic.

It all started when I thought, what if I turned my lemon poppy seed muffins into lemon blueberry? That bright citrus zing with juicy bursts of blueberries felt like the perfect match. But then, inspiration struck—what if I made them even better with a fermented streusel? And just like that, these muffins were born: a long-fermented batter that creates a pillowy, moist crumb with the addition of sour cream and sweet honey, a tangy depth from sourdough, and a crunchy fermented streusel topping for that bakery-style finish.

Why Use Sourdough in Muffins?

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

Do I have to long-ferment these Muffins?

No! You can mix up this batter if you want muffins quickly. Directions will be listed below.

Tools to Gather:

-Mixing bowls- to mix batter

-Whisk & spatula- to mix your batter

-Muffin tin (12-cup)- to bake your muffins

-Parchment muffin liners- to line muffin pan to avoid sticking

-Measuring cups & spoons (or scale for grams)- to measure ingredients

-Strainer & paper towels- for thawing blueberries and draining

-Hand Beaters- for mixing batter

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Now let's make some muffins!

Ingredients:

Step 1: Mix the Base (Night Before – Long Fermentation)

In a large bowl, mix:

• 1/4 cup (85g) honey

• 3/4 cup (150g) white sugar

• 1/2 cup (120g) sourdough discard

• 1/2 cup (120g) sour cream or plain whole milk Greek yogurt (do not use regular yogurt, light sour cream, or non fat Greek yogurt this will affect the texture)

• 2/3 cup (150g) milk

• 3 cups + 1/4 cup (400g) all-purpose flour

Combine your ingredients well with a spatula or dough whisk. You should have a mixture that is fairly thick. Cover and let ferment overnight (8-12 hours) at room temperature. This allows the flavors to develop and improves the muffin’s texture. If you feel nervous about leaving dairy out overnight or your kitchen is very warm (over 72 F), you can cover this mixture and refrigerate overnight. Allow batter to warm up and come to room temperature before proceeding with Step 2 the next morning.

Fermented Streusel:

• 75g all-purpose flour (½ cup)

• 100g granulated sugar (½ cup)

• 30g (2 tbsp) sourdough discard

• 28g unsalted butter, softened

• Pinch of salt

Instructions:

Combine flour and sugar in a bowl. Add softened butter and discard. Use your fingers or a fork to mix until a crumbly texture forms. Cover and let sit at room temperature overnight with the batter.

Note: If you choose to make these muffins same day, you can skip the fermentation step.

Step 2: Complete the Batter (Next Morning)

To the fermented mixture, add:

• 2 tsp (8g) vanilla extract

• 4 tbsp (60g) unsalted butter, melted

• 1/4 cup (60g) avocado oil

• 2 1/2 tsp (10g) baking powder

• 1/2 tsp (1g) baking soda

• 3/4 tsp salt

• 2 large eggs, room temperature (soak in warm water for ten minutes if needed)

• 1 3/4 cup (250g) frozen wild blueberries (thawed in warm water, drained and patted gently dry- tossed in 2 T flour) (weigh before thawing)

Note about blueberries: if using regular larger frozen blueberries- reduce the quantity to 1 1/2 cup (200 g) as they release more moisture and cause batter to be too wet. Weigh before thawing.

Making the Muffins:

Preheat your oven to 425°F (175°C). Rinse frozen blueberries in a strainer with warm water for 1-2 minutes. Let drain on a paper towel and blot well to remove excess moisture. Toss in 1-2 tbsp flour to help absorb extra liquid before folding into the batter.

Add the oil, melted butter, vanilla, eggs, baking powder, baking soda, and salt your fermented base. Using a hand mixer, combine your ingredients together until batter is smooth (this takes roughly 1-2 minutes). Don't overmix your batter.

Add in:

• Zest of 2 large lemons (8g) (add more if you want more lemony muffins)

• 3 tbsp (50g) fresh lemon juice

Mix lemon juice and zest into batter. This helps avoid a reaction with the lemon juice and baking soda to mix in lemon juice later. Gently fold in your blueberries, avoiding overmixing so your batter doesn't turn blue. Line a muffin tin with paper liners or lightly grease it. I love these muffin papers linked here for a bakery-style muffin https://amzn.to/4i3RRXc. 

Divide the batter evenly into the muffin cups, filling each about 3/4 full. This is typically roughly 1/3 cup for a regular sized muffin, I love this scoop here for easy consistent measuring https://amzn.to/41GFGKg.

Spoon 1 big spoonful of fermented streusel on top of each muffin.

Bake for 5 minutes at 425 F, then drop the heat to 350 F and bake 22-25 minutes, or until a toothpick inserted into the center comes out clean. Let the muffins cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely.

Note about baking temperatures: Baking for 5 minutes at a higher heat gives muffins a more domed, bakery-style appearance. If you would like to skip this step, you can bake your muffins at 350 F for 25-28 minutes or until a toothpick comes out clean.

How can I make these muffins without the long fermentation?

If you want to skip the fermentation steps and bake these muffins same day, incorporate the ingredients as listed below.

Wet Ingredients:

• 1/4 cup (85g) honey

• 3/4 cup (150g) white sugar

• 1/2 cup (120g) sourdough discard

• 1/2 cup (120g) sour cream or plain whole milk Greek yogurt (do not use regular yogurt, light sour cream, or non-fat Greek yogurt this will affect the texture)

• 2/3 cup (150g) milk

• 2 tsp (8g) vanilla extract

• Zest of 2 large lemons (8g) (add more if you want a stronger lemon flavor)

• 3 tbsp (45g) fresh lemon juice

• 4 tbsp (60g) unsalted butter, melted

• 1/4 cup (60g) avocado oil

• 2 large eggs, room temperature (soak in warm water for ten minutes if needed)

Blend batter together until smooth for 1-2 minutes with hand beaters.

In a separate bowl, whisk together your dry ingredients.

Dry Ingredients:

• 3 cups + 1/4 cup (400g) all-purpose flour

• 2 1/2 tsp (10g) baking powder

• 1/2 tsp (1g) baking soda

• 3/4 tsp salt

Add dry ingredients to your batter and mix 1-2 more minutes or until batter is smooth.

Mix-ins:

• 1 3/4 cups (250g) frozen blueberries  (thawed in warm water, drained and patted gently dry- tossed in 2 T flour) (weigh before thawing)

Note about blueberries: if using regular larger frozen blueberries- reduce the quantity to 1 1/2 cup (200 g) as they release more moisture and cause batter to be too wet. Weigh before thawing.

Preheat oven to 425 F. Rinse frozen blueberries in a strainer with warm water for 1-2 minutes. Let drain on a paper towel and blot well to remove excess moisture. Toss in 1-2 tbsp flour to help absorb extra liquid before folding into the batter.

Scoop batter (1/3 cup) into a 12-cup muffin tin. Add 1 large spoonful of streusel to the top of each muffin. Bake at 425 F for 5 minutes and then drop heat to 350 F and bake another 22-24 minutes or until a toothpick comes out of center clean.

Makes 16 muffins (if using a 1/3 cup measure)

Storing Tips:

-Store muffins in an airtight container on counter for up to 5 days.

-Freeze muffins in an airtight container for up to 3 months. Allow to thaw and gently reheat in oven or microwave to serve.

These long-fermented sourdough lemon blueberry streusel muffins are sure to be a hit. Drop a comment and leave a review if you loved this recipe! Happy baking!

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