In saucepan, combine 2 cups sugar, 1/2 cup good vinegar and 1/2 cup butter. Bring swiftly to a boil, then continue boiling until it reaches hard stage, 300 to 310 degrees.

Butter a rectangular cake pan and scatter over it 1/2 cup chopped walnuts. Pour candy over the walnuts in the cake pan and let cool and harden. When well hardened, turn pan upside down; rap sharply against the table. The candy will come out in a sheet; break into pieces.