Preheat the oven to 400 degrees F (200 degrees C).

Stir together flour, baking powder, baking soda, garlic powder, mustard powder, pepper, and salt in a medium mixing bowl. Cut in butter until mixture resembles coarse meal. Mix in Cheddar cheese and scallions. Stir in yogurt and milk.

Spoon 1/4-cup mounds of dough 2 inches apart onto an ungreased baking sheet.

Bake in the preheated oven until golden, 12 to 15 minutes. Let cool 10 minutes before transferring to a wire rack to cool completely.