Tender, fluffy muffins bursting with blueberries. A quick breakfast that makes your sourdough discard shine.

Preheat oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or grease well.
In a large bowl, whisk together the sourdough discard, eggs, milk, melted butter, sugar, and vanilla.
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
Add the dry ingredients to the wet and stir until just combined. Do not overmix.
Toss the blueberries with 1 tablespoon of flour (this helps prevent sinking), then gently fold into the batter.
If making streusel, combine the flour, sugar, and cold butter. Pinch together with your fingers until crumbly.
Divide batter evenly among the muffin cups (fill about 3/4 full). Top with streusel if using.
Bake for 22-25 minutes until golden and a toothpick inserted in the center comes out clean.
Let cool in the pan for 5 minutes, then transfer to a wire rack.