Preparation:
1. Combine cocoa, sugar, corn syrup and salt in heavy 3-quart saucepan.
2. Add evaporated milk and water; bring to a boil over medium heat, stirring constantly.
3. Cook, stirring frequently, until mixture forms a firm ball in cold water, or registers 245 F. on candy thermometer.
4. Remove from heat; drop in butter and vanilla, stirring to completely blend in butter.
5. Pour into buttered 9-inch square pan; let cool.
6. Cut into squares (scissors are helpful) and wrap in waxed paper. | 