Espresso Sponge Toffee

Directions

1. 1
   In a saucepan (at least 2 quarts big) on low, heat up the first 4 ingredients (everything except the baking soda). Use a wooden spoon to mix the ingredients together.
2. 2
   Make sure you have a candy thermometer, either clipped to the side of the pan or leaning inside the pan, to monitor the temperature of the mixture while it is heating up. The temperature you want to eventually get to, is 300°F.
3. 3
   Line a baking pan (or brownie pan) with parchment paper or silicon mat (with parchment paper to cover the sides). Or, grease the baking pan if you don't have parchment paper or a silicon mat.
4. 4
   When the mixture is 300 F, turn the heat off.
5. 5
   Make sure there are no lumps in the baking soda and add it to the sugar mixture.
6. 6
   Mix quickly with the wooden spoon while the mixture bubbles up. It will expand to at least 2 times its original volume.
7. 7
   Using the wooden spoon or a spatula, pour and scrape the toffee into the baking pan.
8. 8
   Let it cool for at least 30 minutes before breaking it into pieces.