Step 1

Arrange a rack in the middle of the oven and heat the oven to 425ºF.

Step 2

Place 3/4 cup all-purpose flour, 1 1/2 teaspoons baking powder, and 1 teaspoon kosher salt in a large bowl and whisk to combine.

Step 3

Grate 1 stick cold unsalted butter on the large holes of a box grater. Add the grated butter to the flour mixture and use your fingers to toss and coat the butter in the flour, breaking up any clumps of grated butter.

Step 4

Make a well in the flour mixture and add 1 cup sourdough starter. Stir together with a spatula until a rough, shaggy dough forms.

Step 5

Scrape the dough out onto a clean work surface. Pat the dough into a 1-inch-thick rough rectangle (about 5 x 7-inches), with a long side close to you. Sprinkle the dough with a little more flour, if needed. Fold the dough in half from top to bottom, then pat it back down into its original shape. Repeat with the folding and patting, alternating folding from each side, the bottom, and the top until you have completed a total of 8 folds. At the end, the dough should be a little springy to the touch.

Step 6

Pat the dough until 1-inch thick. Use a 3-inch round cutter to cut out 6 biscuits. If you don't get 6 the first time around, gather the scraps together into a ball, pat back down until 1-inch thick, and cut out more as needed. Discard the scraps of leftover dough.

Step 7

Place the biscuits on an ungreased, unlined baking sheet, arranging them so they just barely touch each other. Bake until golden brown, 18 to 20 minutes. Serve immediately with butter or jam.