Butter a 9-inch by 9-inch pan.

Combine the ingredients in a medium to large-sized heavy pot and cook over medium heat until it reaches (240°F) = (115°C) (or a firm ball stage).

Add the chopped nuts if desired. Pour into the buttered pan.

Let the caramel set overnight.

Cut into one-inch squares and wrap in waxed paper or plastic wrap.

This recipe makes about 50 one-inch squares.