Preheat oven to 450 degrees F (230 degrees C). Line a baking sheet with parchment paper.
Whisk flour, baking powder, salt, and pepper together into a large bowl. Mash grated butter into the flour mixture until the result resembles coarse crumbs. Mix blue cheese, bacon, and 2 cloves minced garlic into the flour mixture.
Make a well in the center of the flour mixture. Pour buttermilk into the well and mix with your hands until the dry ingredients are just moistened. Drop mixture by heaping spoonfuls onto prepared baking sheet.
Bake in preheated oven until lightly browned, 12 to 15 minutes. Switch oven to preheat the broiler.
Stir melted butter and 1 clove minced garlic together in a small bowl; brush over the top of the biscuits.
Heat biscuits under the broiler just until the tops are browned, about 2 minutes.