Place butter in the freezer and let freeze for at least 15 minutes.

Preheat the oven to 425℉.

In a large mixing bowl, combine the dry ingredients. 280 grams all-purpose flour, 70 grams sugar, 5 grams baking powder, 5 grams baking soda, 5 grams salt, 1 teaspoon cinnamon

Shred the frozen butter and mix it into the flour mixture, rubbing with your fingers to get it into small bits of butter, about the size of a pea.114 grams unsalted butter

Wash and pat dry blueberries. Toss blueberries into the flour mixture. 150 grams blueberries

In a separate bowl, mix the wet ingredients.120 grams sourdough discard, 1 large egg, 30 grams milk

Pour the wet ingredients into the dry ingredients and mix with a fork or danish dough whisk until the dough begins to come together.

Dump the scone dough onto a lightly floured surface and gently press it together until the flour is incorporated and the dough forms. At first it will seem like too much flour but it will come together. Avoid smushing the blueberries.

Shape the dough into a circle, about 8 inches in diameter. If the dough is really sticky add a little extra flour.

In a small bowl, prepare the topping by chopping up the butter. Mix it with flour, sugar, and cinnamon until the butter is broken up into little pieces. 28 grams butter, 35 grams flour, 30 grams sugar, ½ teaspoon cinnamon

Brush the scone dough with 1-2 Tablespoons of milk. Press the crumble topping on to the top of the dough. 15-30 grams milk

Cut the dough into 8 pieces using a bench scraper or knife. Place them on a baking sheet lined with parchment paper or silicone mats.

Bake at 425℉ for 15 minutes or until they are lightly golden brown on the edges. Don’t over bake or they will get dry.

In a small bowl, add the powdered sugar, vanilla extract, and milk and whisk to combine until smooth. Add it to a ziplock bag or piping bag and cut one of the corners to make drizzling easy.120 grams powdered sugar, 30 grams milk, ½ teaspoon vanilla extract

While the scones are still warm, drizzle icing on top of the scones and enjoy.