Line a sheet tray with a silicone mat. Set it aside until the brittle is ready to be poured from the pan.

In a heavy bottom pot bring sugar, corn syrup, salt and water to a boil over a medium heat until it reaches 240°.

Add the almonds to the boiling mixture, and stir constantly until the mixture reaches 295°.

Remove from the heat. Add the butter and vanilla at once, and stir until the butter is melted.

Immediately pour onto the prepared sheet pan. You don’t need to spread it out, just let it settle in the pan on its own.

Let cool for at least an hour, and then break into bite-size pieces.