This is great recipe for using the discard from your sourdough starter. The slightly acidic starter will help give your flakey scones a little bite to them.
In a large mixing bowl whisk the flour, sugar, salt, baking powder, and lemon zest. With a pastry blender or your fingers blend in the butter until the the mixture takes on a pebbly consistency. Not all of the bits of butter and flour will be the same size. Add the blueberries.
Mix the eggs, starter, and milk together until combined.
Pour the wet ingredients over the dry and with a spatula gently fold and mix the ingredients until all contents stick together. If your dough is a little dry add additional milk 1 tbsp at a time.
On a lightly floured surface create a mound of dough and shape into a circle about 8 inches in diameter. Using a knife or bench scraper cut the dome into 8 pieces.
Place on a baking sheet lined with parchment paper or silicone mat and place in the refrigerator for 30 min.
Bake for 20-25 min until the tops are a nice golden color. Cool on a cooling rack.
Mix the lemon juice with the powdered sugar until the icing is smooth. You can add more sugar or juice to achieve the desired consistency. Drizzle over the cooled scones.
Notes
It is important to make sure that your sourdough starter is 50% water and 50% flour by weight. If you use a starter that is higher in water the resulting dough will be very loose and wet.