Preheat your oven to 400 F and prepare your muffin tins. You can either use paper liners, or grease them with cooking spray or coconut oil rubbed inside each tin.
In a large bowl, combine the flour, baking powder, baking soda, poppy seeds, sugar and salt.
In a medium bowl, whisk together the sourdough starter, milk, melted butter, eggs, lemon juice and vanilla until well incorporated.
Slowly add the dry ingredients to the starter mixture and gently combine. Be careful not to over mix.
Spoon the batter into the prepared muffin tins.
Bake for 20 minutes, or until a toothpick (or cake tester) inserted in the middle comes out clean. The edges of the sourdough lemon poppy seed muffins should start to turn golden brown.
Remove to a wire rack to cool.
For the glaze, whisk the powdered sugar and lemon juice in a small bowl until combined. You can either drizzle it over the top with a spoon, or add it to a piping bag. I use a ziplock bag with the corner clipped off.
Enjoy!
Long Ferment Option 1:
This is what I typically do, and the muffins in the photos were made this way with a 12 hour ferment.
The night before, add the all purpose flour, sourdough starter, and milk to a bowl and combine.
Cover with plastic wrap, a tight lid, or a beeswax wrap. Allow to sit at room temperature for 8-12 hours.
The next day, add in the baking powder, baking soda, sugar, salt, butter, eggs, lemon juice and vanilla.
Long Ferment Option 2:
I am comfortable allowing the milk to sit out for a lengthy period of time, but this is milk from our farm that we trust. Use discretion here. If you prefer to ferment in the refrigerator, you can mix up the entire batter with all of the ingredients from the original instructions, and put it covered in the fridge for 12 hours or up to 2 days
Notes
Note: if you are uncomfortable with leaving out milk overnight, you could substitute with water.