Ingredients
Method
- In a large mixing bowl, whisk together 500 g all-purpose flour, 2 tablespoons baking powder, and 1 teaspoon fine sea salt. Toss in 170 g unsalted butter until all of the pieces are coated in butter. Using your fingers or a pastry blender, work the butter into the flour until most of it resembles breadcrumbs and none of the pieces are larger than the size of peas.
- In a medium mixing bowl or measuring glass with a spout, whisk together 200 g sourdough discard and 300 g cold milk or water until completely combined. Pour it over the butter and flour mixture. Fold in the wet ingredients until the flour is all hydrated. It will still look rough and shaggy at this point, but the dough should be able to hold together if pressed. If it doesn't, add extra milk or water about 1 tablespoon at a time until it does.
- Pour the dough out onto a clean work surface. Gently pat it into a square or rectangle that's about 1" (2.5 cm) thick. Cut into quarters, and stack the pieces on top of each other. Pat it into a square or rectangle once more, and repeat cutting and layering. Press the final layers together, wrap in plastic wrap, and chill at least 1 hour and up to 2 days.
- Preheat the oven to 400˚F (205˚C). Either line a baking sheet with parchment or a silicone baking mat, or lightly butter a cast iron skillet. Gently roll the dough out until it's about ½" (1.3 cm) thick. Use a circular cookie or biscuit cutter to cut as many biscuits as you can, without twisting the cutter. Gather the scraps together and pat them out to a thickness of about ½" (1.3 cm), and cut out more biscuits. You can only cut scraps once, but you can bake them on the edges of the baking sheet for a chef's snack.If you don't want to deal with scraps, you can roll the biscuit dough to a roughly square or rectangular shape, and use a knife to cut square or rectangular biscuits.
- Whisk 1 egg until the white and yolk are completely combined, and brush some on the top of each biscuit. Be careful not to let any egg wash get on the sides of the biscuits or they may not rise as well. Bake for 25-30 minutes or until tall and flaky and lightly golden brown. Allow to cool on the baking sheet until easy to handle.
- Biscuits are best enjoyed the same day. If you have any leftovers, cut them open and pop them in the toaster so they're (almost) as nice and crispy as they were fresh out of the oven.
Notes
Recipe yield depends on how thick you roll the dough and how large you cut your biscuits. If you use a standard-size biscuit cutter of around 2½-3" (6.3-7.6 cm) and roll your dough to around ½" (1.3 cm) thick, you can expect to get around 12 biscuits.