1. Preheat the oven to 350 degrees. Line a baking sheet with parchment paper or nonstick aluminum foil. Set aside.
2. In a large bowl, sift together the flour, salt and baking powder until well combined (about 30 seconds).
Cut the pieces of cold unsalted butter into the flour mixture until they are tiny and dispersed throughout.
Add the milk and stir well until the dough forms a rough ball.
3. Turn the dough out onto a floured surface (I use a big wooden cutting board). Then knead lightly with floured hands until the dough is a smoother ball. Pat down into a circle. Use a floured rolling pin to roll the dough out until it's 1/2-inch thick.
Use a 2-inch biscuit cutter (or a jelly jar) to cut circles from the dough.
Knead scraps and re-roll the dough as needed until you've used all but a small bit.
4. Arrange the biscuits on the baking sheet. Slide into the oven and bake for 14-15 minutes, until the tops begin to color slightly. Remove from the oven. Turn off the oven and start the broiler. Meanwhile, melt the salted butter and brush the tops of the biscuits with it.
5. Slide the tray bake into the oven and broil for 1-2 minutes, watching very carefully, until the biscuits turn golden.
6. Serve immediately.