Sponge Toffee Ingredients * 1c sugar * 1 c corn syrup * 1 tbsp vinegar * 1 tbsp baking soda Directions 1. Combine sugar, syrup and vinegar in large sauce pan. 2. Stir over med. heat until sugar is dissolved. 3. Continue to cook to 300F(hard crack stage). 4. Remove from heat,stir in baking soda quickly (will become frothy) 5. Pour into a buttered pan. 6. Cool and break into pieces.