Preheat oven to 400 F.

Line a rimmed baking sheet with parchment paper or a silicone baking mat.

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

Using your fingers or two forks, blend the butter into the flour mixture until it resembles course sand.

Stir in the shredded cheese.

In a small bowl, whisk together the milk and sourdough starter until combined, and then mix this into the flour mixture until just combined. Do not overmix. 

Use a spoon to scoop about 2 Tablespoons worth of batter onto the prepared baking sheet, until you have about 12 biscuits.

Bake until just starting to turn golden, about 12-15 minutes. 

While the biscuits, stir together the melted butter, dried parsley, garlic powder and a pinch of salt. 

As soon as the biscuits come out of the oven, use a pastry brush to brush the butter onto the biscuits.

Allow the biscuits to cool on the pan for a few minutes before enjoying warm.