Preheat to 425°F; line baking sheet.
Whisk flour, baking powder, and salt; cut in butter; stir in sour cream and milk for dough.
Roll and fold dough three times; cut 12 biscuits; bake 10–12 min; brush with butter.
Brown sausage 5–8 min; whisk in butter and flour 2 min; add milk and cook 8–10 min; season.
Split biscuits; spoon gravy over top; serve.