Combine flour with baking powder, sugar, and salt. Use a pastry cutter, your hands, or a food processor to blend in cold butter and cream cheese until the mixture resembles coarse sand. Stir in the chopped scallions and milk, mixing just until combined.
Shape the biscuit dough into a square about 1-inch thick and cut into 4 pieces. Stack the pieces on top of each other and flatten again until the square is 1-inch thick. Wrap the dough in plastic and chill for 30 minutes.
Preheat oven to 425 degrees F.
Lightly dust a clean work counter with flour and roll out the dough until it's ½-inch thick. Cut the dough into 9 equal squares and place them on a lined baking sheet. Brush the tops with milk or melted butter and sprinkle everything bagel seasoning on top. Bake the biscuits for about 12 minutes or until golden brown. Remove from oven and serve warm.