Line a baking sheet with parchment paper or a silicone mat.
In a large mixing bowl, whisk together the flour, baking powder, baking soda, salt, and black pepper.
Grate in the cold butter. Cover the butter in the flour mix, pinching the butter to make a crumbly mixture.
Add the cheese and jalapeno and mix to cover them in flour.
Make a well in the center and pour in most of the buttermilk. You may not need it all. Mix together to end up with a shaggy dough. Don't over-mix, just bring the dough together with your hands until it just holds together. If the dough is too dry and doesn't stick together, add more buttermilk as needed.
Turn the dough out onto a lightly floured surface. Press the dough out flat until it's about 1 inch thick. Use a cookie cutter or biscuit cutter to cut out circles.When cutting out the circle press straight up and dough with your cutter and do not twist the cutter – this prevents the biscuits from rising fully in the oven because it presses the edges together and seals them.
Alternatively, you can use a knife and cut the dough into squares.
Bake for 12-15 minutes or until the tops are golden brown.
Notes
Always use cold butter for biscuits. You can freeze it for 10 minutes before grating it.Don't overwork the dough. Don't twist the biscuit cutter. To make buttermilk combine 1 cup of milk with 1 tablespoon of vinegar. The buttermilk adds a tangy flavor, contributes to the rise, and yields a soft tender dough.When measuring flour, I go by 120 grams per cup. If you’d like to use cup measurements for the flour, then measure by spooning your flour into the measuring cup, and not digging your cup into the flour. You’ll get the best results by using a scale though.Substitutions - Leave out the jalapenos if you want to. Try different cheeses.Store at room temperature, covered for about 3 days.