Grease and line a metal cake pan we used wax paper, but greased parchment paper is often recommended. (Do not be tempted to use a glass pan, you want something that has some bend to it).
Get your baking soda and vanilla ready.
Stir sugar, corn syrup and water in a 12 cup pot over medium heat until sugar dissolves.
Put in a candy thermometer. Do not stir while you wait for it to come to a boil.
When the temperature reaches 300F (hard crack stage) remove it from heat.
Quickly whisk in the baking soda. This will cause the mixture to bubble up (you’ll want your kids who are not actively helping to stay back – it’s hot!)
Whisk in the vanilla.
Immediately pour into the prepared pan. Let it cool in the pan for about 2 hours. The mixture may be kind of uneven on top but resist the urge to smooth it out, that will pop the air bubbles.
Break it into pieces and enjoy!
Recipe by Talking in ALL CAPS at https://talkinginallcaps.com/2013/01/surprisingly-easy-sponge-toffee-recipe-dairy-free.html