In a medium bowl, combine the butter and the cheese. Beat at medium speed until well-combined. In a separate bowl, combine the flour, salt, and black and cayenne pepper. Add to the cheese mixture and beat on low until blended. Add the nuts and stir until well-combined. Lightly flour a cutting board. Place the dough atop and divide it in half. Form each half into a log shape about one inch wide. Wrap in plastic wrap and refrigerate until firm. Preheat oven to 350°F. Slice the chilled dough into ¼-inch-thick biscuits and place two inches apart on ungreased baking sheets. Bake for about 10-12 minutes, or until edges are brown.