Preheat oven to 425°. Line a baking sheet with parchment paper and set aside.

In a large bowl stir together the baking powder, salt, sugar, and
flour.

Add the chilled butter pieces and use your fingers to smash the butter into the flour. The dough will resemble pebbled sand.

Add the sourdough starter to the bowl and mix gently to combine. Do not overmix, just mix until the dough comes together.

Transfer the dough to a well floured surface and pat it out to 1/2 inch thickness.

Fold the dough into thirds like a letter to create a rectangle. Turn the dough 90 degrees and fold it into thirds again. Turn the dough 90 degrees and repeat the tri-fold.

Pat the dough out to 1 inch thickness and then cut out rounds using a 2 or 3 inch biscuit cutter. Place on the parchment lined baking sheet at least 1 inch apart.

Bake biscuits until gold brown, about 12-15 minutes.