Step 1

Preheat your oven to 375 F/ 190 C. Line a 12-cup muffin pan with paper liners.

Step 2

Sift the flour, baking soda and salt together in a small bowl; set aside.

Step 3

Whisk the sourdough starter and milk together in a separate small bowl; set aside.

Step 4

In a stand mixer fitted with the paddle attachment (or by hand with a wooden spoon): cream the butter, sugar, vanilla extract and zest together. Add the eggs, one at a time, beating well after each addition.

Step 5

Working in batches, add 1/2 of the flour mixture. Once absorbed, add half of the milk mixture. Repeat until everything is used up and the batter is smooth and well incorporated.

Step 6

Fold the blueberries into the bowl with a rubber spatula. Make sure to evenly distribute the berries throughout the batter (check the bottom of the bowl!).

Step 7

Fill the muffin pan, about 3/4 of the way full. Top with a few berries if you like, making sure to tuck them in so they don’t pop out during baking.

Step 8

At this point, you can bake right away or chill overnight, for 12+ hours.

Step 9

To bake now: place the tin on the center rack and bake for 25-28 minutes.

Step 10

To bake later: remove the tin from the refrigerator; discard the foil. Bake straight from cold for 25-28 minutes.

Step 11

Cool the muffins in the pan for 15 minutes. Transfer to a wire rack to finish cooling so the bottoms don’t get soggy.

Step 12

Serve warm or at room temperature with powdered sugar.