Prepare a large sheet pan with parchment paper or lightly grease pan with butter, sprinkle on flour, and turn upside down to get rid of excess.

Combine flour, baking soda, baking powder, garlic powder, onion powder, pepper, salt, and shredded cheese in a mixing bowl.

Use a cheese grater to shred butter or cut cubes of butter into the flour mixture with a fork until pea-sized.

Add in water and sourdough starter, mixing until combined (if you can't get all the flour combined right now, that's okay).

Turn dough out on the counter and combine fully with your hands; don't knead (add 1-2 Tbsp extra liquid if needed).

Fold dough in half, then in half again. Do this twice to create layers.

Use your hands to gently form a 6x8 rectangle about 1 1/2 inches thick (don’t overwork the dough).

Cut biscuits out with a biscuit cutter or mason jar with a straight up-and down motion. Do not turn the cutter; it’ll seal the biscuits and prevent layers. Place each biscuit on the sheet pan 1-2 inches apart.

When done cutting biscuits, don’t combine the excess dough for more cutting. Instead, roll the excess dough into 4 logs to place around the biscuits on the outer edges of the baking sheet.

Place in the oven and bake at 400 degrees Fahrenheit for 16–20 minutes (tops will be golden brown and set).

While the biscuits are baking, add melted butter, garlic powder, pepper, parsley (optional), and salt in a small bowl, stirring until combined. Set aside.

When biscuits are finished baking, immediately brush them with the garlic butter on the tops and sides until all is used up. Enjoy!