In the time it takes to take a shower, listen to three Paul Simon songs, or prepare a cup of tea, you can make biscuits. This is the very best version of pared-down, no-frills biscuit. You don't even need buttermilk! You can make them ahead and pop them in the oven to reheat, or freeze the cut-out biscuit dough and bake them off whenever you want. —Posie (Harwood) Brien
Preheat the oven to 410 degrees. Anywhere from 400-425 degrees will work just fine -- biscuits are decidedly NOT finicky in terms of oven temp and time.
In a large mixing bowl, whisk together the flour, salt, and baking powder. Cut the butter into chunks, add it to the flour mixture, and (using a fork or a pastry cutter), cut it into the flour mixture until it is in pea-sized pieces. You really need to keep the butter in little bits -- this is what makes the flakes in the biscuit!
Pour the milk into the bowl and, using a fork or spoon, stir the milk until it is incorporated. The dough is going to feel much too dry in some places -- that is okay. [OPTIONAL: You can also add in a beaten egg with the milk. I like biscuits both ways. It just makes them a little more buttery if you add the egg here.]
Now, using clean hands, start folding together the dough in the mixing bowl. The goal here is to incorporate all the dry ingredients without overworking or overwarming the butter. Just keep folding it over itself a few times. The idea is to keep the little bits of butter distinct and not let it all melt together, so you need to have a very light touch. The more your dough has visible bits of butter, the better your biscuits (say that 3 times fast).
Now turn the dough out onto a floured surface and fold it over on itself, pressing down gently to knead it together as you go. Once it is all well-mixed, roll it out into a disc about 2 inches high. Using a pastry cutter or some other metal round, punch out circles of dough (make them as big as you want!)
Place the dough circles on an unlined baking sheet. Brush the tops lightly with a beaten egg (this is optional but it makes them prettier). Bake them for about 10-15 minutes...keep an eye on them after 10 minutes and pull them out as soon as they start to get golden brown.