1 cup pure maple syrup
1/2 cup granulated sugar
2 tsp distilled white vinegar
2 tsp baking soda
1. Butter a 9x9-inch pan and set aside.
2. In a heavy 2-quart saucepan, combine the syrup, sugar and vinegar. Bring to a boil over medium heat, stirring constantly until the sugar dissolves. Continue cooking without stirring until a candy thermometer reads 300 degrees F.
3. Remove from heat and quickly stir in the baking soda; mix well. Pour into the prepared pan. Do not spread. Cool and break into pieces.
