1. Heat oven to 450 degrees F. Grate the cheese in a food processor, then remove the cheese from the bowl. Add the flour and cayenne to the bowl and pulse. Cut the butter into pieces, then toss it in. Process until butter and flour are combined.
2. Remove the dough from the bowl and stir in the cheese. Knead by hand until it comes together, adding a few drops of ice water (no more than 1 tablespoon) if necessary. You may prepare the recipe in advance up to this point; wrap well in plastic and refrigerate for a day or two before proceeding.
3. Divide dough in half and roll one half to 12 x 7-inch rectangle, then cut crosswise into strips, each about 1/2 inch wide. Place on lightly greased baking sheets and sprinkle with salt (optional). Repeat with remaining half. Bake until golden brown, 5 to 8 minutes. Serve hot, warm or at room temperature.