Preheat the oven to 400 degrees Fahrenheit and prepare a baking sheet with parchment paper or lightly grease with butter and a dusting of flour.
Combine flour, salt, and baking powder in a large bowl.
Grate the butter or use a fork to cut the butter into flour to form pea size pebbles.
Add in sourdough starter, milk, jalapenos, and cheese.
Mix ingredients until a dough forms. Avoid overmixing.
On a lightly floured surface, turn your scone dough out onto the countertop.
Use your hands to shape fold the dough 2 times into an envelope shape to create layers.
Then use your hands again to shape the dough into a 2-3 inch high circle.
Take a knife or bench scraper and cut dough into 8 pieces like a pie.
Place scones on the prepared baking sheet one by one onto the sheet pan about 2 inches apart.
Bake for 16-18 minutes. The bottom of the scones should be golden brown.
