Direction :

1. Combine the flour, baking powder and salt in a bowl and put it in the fridge for 20 to 30 minutes. In the meantime, cut the butter into chunks and leave out at room temperature (you want it malleable, but not soft).
2. Position a rack in the center of the oven and heat it to 400 degrees. Line two baking sheets with parchment paper. Combine the chilled dry ingredients, the cheese and the butter in the bowl of a standing mixer fitted with a paddle attachment. Mix on low speed for a few minutes, until the chunks of butter are no bigger than a large pea – or a small bean. (In the oven, the water in the chunks of butter creates steam, which in turn will creates lovely pockets of air within the biscuits.)
3. Add the buttermilk to the bowl and mix on low just until the dough comes together. Turn the dough out onto a floured board, dust your fingers with flour and gently knead it a few times. Quickly and carefully pat the dough into a large rectangle about 1/2 an inch thick.
4. Dip a 3-inch round cutter with sharp edges in flour and then cut the biscuits using an even downward motion, without twisting the cutter. Transfer the rounds of dough to the baking sheets, leaving an inch or two of space between them. When you’ve cut the first batch of biscuits, gently pat the dough into another rectangle and cut a few more — discard the dough or add the funky leftover shapes to the baking sheets after the second batch is cut (if you shape the dough a third time, the biscuits will be tough).
5. Beat the egg with a splash of water (if you’re feeling fancy, you can then pass it through a fine mesh sieve to get rid of any clumps of egg white that might burn). Brush the tops of the biscuits lightly with egg wash* and bake for about 20 minutes, rotating halfway through, until the biscuits are a deep golden brown. Cool for a few minutes on the baking sheets but serve them while still warm!*At this point you can stick your prepared pan in the freezer. Once the biscuits are frozen, transfer them to a freezer bag to store. When you are ready to bake, there is no need to thaw the biscuits. Just bake them straight from the freezer. I had to cook mine about 3 minutes longer when baking them from the freezer. And I did apply the egg wash before freezing them — worked beautifully.