I don't want to be redundant, but those recipes are strange. Toffee has not to be so complicated and precise. Toffee is essentially amorphous sugar with cream. Thus, what we do is to melt sugar, add cream and prevent the sugar from crystallizing by using butter. This is why you cannot make fat-free toffee. Use only cream and sugar, and you will get something of the same colour, but crystalline in form.

Here are what you need for the most basic form of toffee imaginable:

Remember mix all the time, or the sugar will stick to the bottom. You have to have a wooden spatula, because you can crush lumps of sugar with it. Sugar sticks to metal - and don't even think of a rubber spatula!
  1. Heat the kettle up with full power.
  2. If the spatula is made of wood, wet it under the tap with cold water before touching any molten sugar with it. Sugar will stick to dry wood.
  3. Add the sugar in slowly. If you put all the sugar in quickly, lumps will form. Crush them if they appear.
  4. Decrease the heating power to half when almost all has been melted. Notice how the color of the sugar changes to brown. This gives a caramel taste (as opposed to clean white taste).
  5. Pour the cream in slowly. Fierce boiling and bubbling results. If you pour it in too quickly, the cream will cool the mixture down, the boiling stops and crystallization can start.
  6. When the boiling has set on, add the butter. At this point, the mixture is as liquid as cream.
  7. Boil the toffee to remove water, until only a few bubbles form per second. (The point is that you want to boil away water, and when there's no water to remove, it's ready.) The viscosity will change so that the spatula meets the resistance of toffee, not watery sugar-cream. (Some recipes call for placing a drop in cold water and testing if it solidifies, but this is unnecessary.)
  8. Pour the toffee on the brown paper. You have only a few seconds to scrape the remains from the saucepan, because it cools down quickly and hardens rock-hard.
  9. Clean the utensils with hot water.

There are mistakes to specifically avoid:

  • Keeping it boiling too long.
  • Using too much cream.
  • Not mixing.
  • Setting the heating power any hotter than half of the full. Yes, the boiling might be slow, but when the whole mixture is froth, it will burn.
You do not want to burn it. The nasty, black, foul-smelling, extremely staining burnt toffee will not surrender to even steel wool. Boiling cleaning soda for a long time (hours) can remove the stains.

Thanks BlueDragon