One of the easy ways to use up your sourdough discard is to bake it into fluffy sourdough blueberry muffins. All you need is your discard (or an active sourdough starter), 6 simple ingredients you probably have in your pantry, and some fresh or frozen blueberries.
Simply mix your dry ingredients (flour, baking powder, and salt) in a medium bowl. Make sure to mix them a little, so the baking powder gets evenly distributed.
In a large bowl, mix your wet ingredients; sourdough discard, egg, sugar, olive oil, and vanilla extract if you choose to use it. You can mix the wet ingredients with a hand mixer to ensure they are mixed well.
Measure out your blueberries in a small bowl and coat them with some flour.
Slowly add your flour mixture (dry ingredients) to your wet ingredients. I suggest using a hand mixer at first, but the batter will probably thicken too much for the hand mixer to handle it. Finish mixing the batter with a big wooden spoon (or a regular one).
Finally, gently fold in your blueberries. Doing this with a silicone spatula tends to be the most gentle way to fold them in.
You can go both ways here: If you prefer to have muffins that look more purple, mix them in a bit rougher. If you like a yellow muffin, be extra gentle, and blueberries (especially frozen ones) won't release much juice into the batter.
Line your muffin tin (muffin pan or muffin tray) with muffin liners. Spoon the muffin batter into the prepared liners.
You should have just enough batter to fill 12 muffin cups to about ¾ full. Don't worry, the muffins will rise in the oven!
Place the muffin tin into the preheated oven and bake them at 375°F (190°C) for about 20 minutes or until a toothpick inserted in the middle comes out clean.
If you remember to do so, rotate them at the 10-minute mark to ensure they brown evenly.
Wait for 10 minutes or so, then transfer each muffin to a wire rack to cool completely.
Notes
You can bake these muffins without muffin liners if you want. In that case, after taking them out of the oven, wait for 10 minutes for them to cool down just a bit. Then use a knife to run along the edges of each muffin and carefully pull them out of the pan. Put them on a wire rack to cool completelyDon't skip the step of coating blueberries in some flour! This helps them to mix into the batter smoother and prevents them from sinking to the bottom of the muffins.If you keep a sourdough starter that is more on the thicker side, the batter may end up too thick. Since the recipe is designed with a 100% hydration sourdough starter discard in mind, you can add a splash of water to the batter if you find it too thick.Make sure to cool your muffins properly, on a drying rack. If you leave them in a muffin tin to cool, the muffin liners will become soggy and very unappetizing.Don't skip baking powder or baking soda or you'll end up with a tough muffin. Even if you're using a fairly active sourdough starter, we're not giving it enough time to be the leavener in this recipe.