Cook bacon until crisp; drain on paper towels, then finely chop.
Preheat oven to 400°F. Line baking sheet with parchment paper.
In large bowl, whisk together flour, baking powder and salt.
Cut butter into large pieces and add to flour mixture. With pastry blender or two knives, cut in butter until mixture resembles coarse crumbs.
Add cheese, scallions and reserved bacon and mix lightly. Stir in milk just until no dry flour remains (do not over-mix).
Turn dough out onto lightly floured surface and pat into 1/2-inch-thick circle. Cut out 4-inch circles and place, separated, on prepared baking sheet. Press scraps together and cut out additional biscuits.