Toffee - Caramel or Treacle

based on Margaret Powell - Sweetmaking for Children

Sugar (caster or granulated)         12oz / 300g
Butter                                                     3 1/2oz / 90g
Milk                                                          1/4 breakfast cup / 70ml
Golden Syrup or Treacle                 1/4 breakfast cup / 70ml
Vanilla essence                                   few drops (I don't bother)
Heavy bottomed pan
Greased tin
Jam thermometer is useful.

alternatively, replace milk and syrup with 1/2 breakfast cup / 140ml of sweetened condensed milk.
(may be worth trying molasses and seeing if it works better than treacle - I haven't tried tho)

Put everything except the vanilla essence in a heavy bottomed pan.

Make sure the sugar has dissolved fully at low heat.

Bring to boil, then cook(simmer) slowly for 25-30 minutes. DON'T STIR ONCE BOILING (if the base burns slightly, you stand some chance of rescue if unstirred, I was also told the mix tends to form crystals and become fudge-like or gritty if stirred/ whisked)

When temperature reaches Hard Ball (forms a glassy hard lump when you drop some of the mix into cold water,) - a temperature dangerously close to burning the toffee - add vanilla essence (or don't) and pour the mix into the greased tin.
IT IS VERY HOT AT THIS POINT. DON'T POKE IT WITH YOUR FINGERS.
For softer toffee, take to a slightly lower temperature (Soft Ball).
I'm guessing if you heat even lower and whisk hard (ideally electric) you'll get fudge, but that's a guess, so I can only say this works as toffee.

Once the mix is cooled a bit, mark into squares with a knife.
Then discover that the marking makes little difference once cold and end up with jagged edge pieces of toffee anyway.

Ideally, you should end up with something resembling a piece of glass, which is slightly chewable once you've had it in your mouth a while, but will remove fillings.