Gather all ingredients and equipment. Preheat oven to 450°F and line a baking sheet with parchment paper.
In a small bowl, mix together the milk and apple cider vinegar and allow to curdle for a few minutes. In a large mixing bowl, mix together the flour, baking powder, and salt.
Cut in the butter and shortening into the flour and mix until sandy. Mix in the cheese, black pepper, and scallions.
Make a well in the center and add the curdled milk. Stir until the dough comes away from the sides of the bowl.
Turn the dough onto a floured surface and knead gently 8 to 10 times. Roll out about 3/4 to an inch thick. Cut with a 3 inch round cutter.
Place the biscuits onto the lined sheet pan about two inches apart. Brush the tops with the melted butter. Bake until lightly browned for 12 to 15 minutes.