Sponge Candy or Seafoam

This recipe is a great favorite of my mother's, and it is her mother's recipe. I have heard her reminisce about the big chunks of it available at the BYU candy counter back in the day. I think Iggy is quite fond of it too. It is quite like the Australian candy bar "Violet Crumble."

1 c sugar
1 c dark corn syrup
1 T vinegar (Mom uses apple cider)
1 T baking soda

Combine sugar, corn syrup and vinegar in a heavy saucepan. Cook over medium heat, stirring until sugar dissolves. Continue cooking, without stirring, to 300 F, or until a little of the mixture dropped in cold water becomes very brittle. Remove candy from heat. Quickly stir in soda; mix well. Stir thoroughly so that the cell size is small enough, or the candy will collapse. Every year, Mom is afraid that she has over-stirred it. But she has not. But she has had over-stirred seafoam, so it's possible. Pour into lightly buttered 8 by 8 or 9 by 9 by 2 inch pan. Do not spread as candy. To break into even pieces, score twice or more with serrated knife and break apart by hand-- this will yield relatively even pieces.