Line 2 baking sheets with parchment paper or foil; set aside. In a medium bowl, combine the cheddar cheese and butter. Let stand at room temperature for 30 minutes.
Beat the cheese and butter with an electric mixer on medium speed until well mixed. Add thyme and cayenne pepper; beat until combined.
Using a wooden spoon, stir in flour and finely chopped pecans until combined. Form into a ball, using your hands to knead gently if necessary. Shape into an 8-inch-long log. Wrap with plastic wrap. Chill about 4 hours or until firm.
Preheat oven to 350 degrees F. Using a sharp knife, cut log into 1/8-inch-thick slices. Place on prepared baking sheets. Bake about 10 minutes or until lightly browned. Transfer crackers to a wire rack; cool. Makes about 60 crackers.
Layer cooled crackers between waxed paper in an airtight container; cover. Freeze for up to 2 weeks.