Preheat the oven to 450F and line a baking sheet with parchment paper.

In a large bowl, whisk together the flour, baking powder and salt.

Add the butter to the flour, and using your fingers or a pastry blender, break up the butter until it is the size of peas. You want your butter to be cold so work quickly.

In a small glass measuring cup add the egg and whisk together. Add the milk or buttermilk until it reaches the 3/4 cup mark. Add the milk mixture to the flour mixture and gently mix together to combine. Be careful to not overmix- the dough will look rough but should hold together and have all of the flour incorporated. You can add a couple of teaspoons more of milk if you need to.

Transfer the dough onto a floured countertop and pat together into a circle that is 1" thick. Using a round biscuit cutter, cut the biscuits into circles. Press together the scraps gently to avoid waste and cut again. Alternately, use a sharp knife and cut the dough into 6-8 wedges. Place the biscuits on the prepared baking sheet, leaving space between each of the biscuits, and bake until they are golden, around 12 minutes. Serve warm with butter if desired.