When my sourdough starter is extra bubbly and I have more than I need, these muffins are where it goes. The starter adds a gentle tang and a soft, tender crumb, the blueberries burst as they bake, and the cream cheese center makes every bite feel like a bakery treat.

These are made with regular granulated sugar and measured in grams, so they come out the same every time.

Key Ingredients & Why They Matter

Active Sourdough Starter

Use your starter when it's bubbly and at its peak. It gives the muffins lift, flavor, and a soft texture. Short on starter? For every 80 g you're missing, add about 40 g extra flour and 40 g extra milk.

The Cream Cheese Filling

Keep the filling chilled until you're ready to scoop. Cold filling holds its shape and stays right in the center instead of sinking or melting out.

Blueberries

Fresh or frozen both work. If you're using frozen, add them straight from the freezer and toss them in a spoonful of flour first so they don't sink.

Ingredients

Cream Cheese Filling

• 170 g cream cheese, softened (about 6 oz)
• 50 g granulated sugar (¼ cup)
• 2 g vanilla extract (½ tsp)

Muffins

• 240 g all-purpose flour (2 cups)
• 4 g baking powder (1 tsp)
• 3 g baking soda (½ tsp)
• 3 g salt (½ tsp)
• 150 g granulated sugar (¾ cup)
• 113 g unsalted butter, melted and cooled (½ cup)
• 240 g active sourdough starter (about 1 cup)
• 2 large eggs
• 80 g milk (⅓ cup)
• 5 g vanilla extract (1 tsp)
• Zest of 1 lemon (optional)
• 225 g fresh or frozen blueberries (1½ cups)
• 25 g granulated sugar for topping (2 tbsp)

Instructions

1. Make the filling. Beat the cream cheese, sugar, and vanilla until smooth. Refrigerate while you make the batter.
2. Preheat. Heat the oven to 425°F (220°C) and line a 12-cup muffin tin.
3. Mix the dry ingredients. Whisk together the flour, baking powder, baking soda, and salt.
4. Mix the wet ingredients. Whisk the sugar into the melted butter, then gently whisk in the starter, eggs, milk, vanilla, and lemon zest. Don't beat hard. You want to keep those starter bubbles.
5. Combine. Fold the wet into the dry just until no dry streaks remain. Toss the blueberries with a spoonful of flour and gently fold them in.
6. Layer. Fill each cup about halfway with batter. Add a heaping teaspoon of cold filling (about 15 g) to the center, then cover it with a spoonful of batter so it's sealed in. Sprinkle the tops with sugar.
7. Bake. Bake at 425°F for 5 minutes, then without opening the door, lower the oven to 350°F (175°C) and bake 17–20 minutes more, until the tops spring back and a toothpick in the muffin (not the filling) comes out clean.
8. Cool. Let them cool in the tin for 10 minutes, then move them to a rack.

Tips for the Best Muffins

• Fill the cups no more than ¾ full. Active starter gives these real lift.
• If your starter is on the runny side, cut the milk to 60 g.
• Make sure the filling is fully covered with batter so it doesn't brown or leak.
• Store leftovers in the fridge because of the cream cheese filling.