Heat a skillet over medium heat and cook sausage, breaking it into crumbles, for 8–10 minutes until browned. Drain excess fat and let cool slightly.

Preheat oven to 425°F (220°C) and line a baking sheet with parchment.

In a large bowl, whisk flour, baking powder, baking soda, and salt. Cut in cold, cubed butter until the mixture resembles coarse crumbs. Stir in cold buttermilk just until combined; dough will be slightly sticky.

Turn dough onto a floured surface, knead lightly 4–5 times, then roll to ½-inch thickness. Cut into rounds with a biscuit cutter.

Place a spoonful of sausage on half the rounds and top with the others, pressing edges to seal. Arrange on the baking sheet, brush with melted butter, and bake 12–15 minutes until puffed and golden.

Cool a few minutes before serving warm.