Preheat your oven to 450, line a baking sheet with parchment paper
You can cut your butter into tiny dice, but I prefer to put it in the freezer for a 15 minutes then grate it with the bigger holes on the box grater. Set aside
Mix the first 5 ingredients in a large bowl
Cut the butter into the flour mixture. You can use a pastry cutter or two knives - simply run your butter knives through the dough until the butter is incorporated and you have different sized pieces, some will be pea sized, that's perfect.
Add the buttermilk, mix 3 times, then add the cheese and jalapenos and mix until it's almost combined. Don't overwork the dough!
Dump the dough onto a floured board
Pat the dough until it is about an inch thick, then fold it over itself and pat down again to create those beautiful layers. Do this 4 times.
Use a pastry cutter or anything circular to cut the biscuits into circles. You can also cut them with a knife but try to press down and straight back up i.e avoid a sawing motion
Place the biscuits an inch and a half apart on a baking sheet about 10 minutes or until they are a beautiful golden brown
Press the remaining scraps together and make more biscuits until the dough is used up. Makes 10 2 1/2 inch wide biscuits.
Food Processor Instructions: Pulse twice to mix the first 5 ingredients, then add the butter and pulse a few times until the butter is roughly incorporated. Add the buttermilk pulse 3 times or until the buttermilk seems halfway incorporated. Then add the cheese and jalapenos, pulse twice. The dough should be roughly combined now.