1/4 cup cream or half-and-half, plus more as needed
Coarse salt, pepper, sesame or poppy seeds, minced garlic or whatever you like for sprinkling, optional
Heat the oven to 400 degrees F. Line a baking sheet with parchment paper or lightly dust with flour. Put flour, 1/2 teaspoon salt, cheese, and butter in bowl of a food processor. Pulse until flour and butter are combined. Add about 1/4 cup cream or half-and-half and let machine run for a bit; continue to add liquid a teaspoon at a time, until mixture holds together but is not sticky.
Roll out dough on a lightly floured surface until 1/2-inch thick or even thinner, adding flour as needed. Transfer sheet of dough to prepared baking sheet (drape it over rolling pin to make it easier). Score lightly with a sharp knife, pizza cutter or a pastry wheel if you want to break crackers into squares or rectangles later on. Sprinkle with salt or other topping if you like.
Bake until lightly browned, about 10 minutes. Cool on a rack; serve warm or at room temperature or store in a tin for a few days.