Steps

1. Set a silicone mat on a baking tray and preheat oven to 225 °F.
2. Combine water, sugar, and glucose syrup in a heavy-bottomed pot. Cover and bring to boil, and cook a few minutes until sugar dissolves.
3. Uncover and cook to 239 °F.
4. Stir in peanuts. Continue to cook, stirring constantly, to 311 °F.
5. Cut heat. Stir in butter, then ground salt and vanilla extract.
6. Add baking soda and stir in well, just until foaming is visible and evenly mixed. Do not over mix, which would reduce the foam.
7. Pour onto the silicone mat and spread to even thickness.
8. Allow to cool until centre starts to become pliable; edges will be somewhat firm.
9. Place in oven to even the temperature so the entire mass is a pliable texture, about 1/2 hour.
10. Quickly stretch brittle evenly in all directions, then cool.