Preheat your oven to 325˚F and line 2 baking sheets with parchment paper.
Toss the cheese, flour, and salt into a food processor. Pulse it a few times. Add in the butter and pulse until the dough is crumbly.
Pour in the cold milk, pulse a few more times. The dough won’t form a ball, but it should come together when you press it between your fingers.
Transfer the dough to a lightly floured surface. Roll it out into a big, thin rectangle – thinner than ⅛-inch to account for puffing during baking.
Use a knife, pizza cutter, or fluted pastry wheel to slice it into 1-inch squares. Poke a hole through each cracker with the flat end of a skewer. Sprinkle with more salt.
Bake for 17-20 minutes until they’re a deep golden brown at the bottom. Too light and they won’t be crispy. Let them cool completely before indulging!