1. Melt butter in medium saucepan. Stir in sugar, cocoa, corn syrup and water.
2. Cook over medium heat, stirring constantly until mixture reaches
260°F on candy thermometer or until syrup, when dropped into very cold water, separates into threads which are hard but not brittle. (Bulb of candy thermometer should not rest on bottom of saucepan.) Remove from heat; stir in nuts.
3. Immediately spread mixture about 1/4 inch thick onto ungreased cookie sheet. Cool on wire rack. Refrigerate until cold. Remove from sheet; break into pieces. Store in tightly covered container in refrigerator. About 1-1/2 pounds.