This may or may not qualify as 'butter toffee' according to your local food laws, but with this recipe you can make, at home, what is quite possibly the most delicious toffee - some say caramel - you've ever tasted.

Hardware

• A large, heavy-gauge saucepan, about 7 litres (1 1/2 gallons). The pan from a pressure-cooker is ideal
• A smaller, not quite so heavy saucepan
• Three wooden spoons
• A small bowl or dish
• A sugar thermometer
• A pair of good oven-mitts
• A bowl of iced water
• Two greased toffee trays - approx 30cm x 20cm (12" x 8")

Ingredients

• 700g (24oz) granulated sugar
• 700g (24oz) glucose syrup (light corn syrup in North America)
• 700g (24oz) full-cream, sweetened condensed milk
• 300g (10oz) hard vegetable fat - any non-animal pastry fat/shortening will do
• 60g (2oz) unsalted butter
• 1tsp salt
• Vanilla essence to taste (4 - 8 drops should be about right)

Method

Warning: Boiling sugar syrup is much hotter and stickier than boiling water and can burn very deeply, very quickly. Take great care when boiling sugar, and always have a large bowl of iced water and a first-aid kit nearby in case you get any on your skin.

While this can be made using an electric hob, a gas ring is by far the best way to cook toffee.

1. Firstly, weigh out the ingredients, leaving the glucose until last. Once weighed, pour and scrape the glucose into the small bowl or dish. Next, place the vegetable fat, cut into small pieces, into the smaller pan and set it on a low heat - just warm enough to melt the fat. When it has completely melted, add the condensed milk, turn down the heat to the lowest setting, and stir slowly with a whisk. By the time the sugar and glucose reach the correct temperature (see below), you should have as close to an emulsion as you can achieve.

2. Put the sugar into the large pan and gently, without splashing, pour in barely enough cold water to cover it. When making any kind of boiled sugar syrup confection, try to use the least possible amount of water - the whole point of boiling is to drive off the water you've already added to dissolve the sugar. At this point, and until you add the fat and milk, it's important to try and avoid getting any sugar crystals on the side of the pan - these can re-crystallise after the toffee has cooled and turn it 'grainy', so do not stir it yet. Grainy toffee has crunchy crystals of sugar in it - we're going for a super smooth toffee here.

3. Place the pan over a high heat and wait for the sugar and water to boil. By the time it comes to a rolling boil, the sugar should have dissolved, so pour in the glucose syrup. This is another way of avoiding graininess - glucose is used in most sweets and its purpose is to prevent the sugar re-crystallising after the product cools. If, however, you add the glucose before the sugar has completely dissolved it can enclose the sugar grains and prevent them from dissolving fully, so that they easily re-crystallise in the finished product.

4. Begin gently stirring the syrup when the glucose goes in so that it doesn't sit at the bottom of the pan and burn. Glucose syrup can be quite viscous at room temperature, so it's a good idea to put two wooden spoons across the top of the pan and rest the upturned bowl or dish containing the glucose on top so that the remaining glucose drips into the pan as the syrup cooks. Remove it (and the wooden spoons) as soon as soon as it is empty. Use the oven mitts - it will be very hot.

5. When the glucose has melted you no longer need to stir the syrup, so place the sugar thermometer into the pan. Sugar thermometers are usually made with a large loop at the top - a good tip is to get about 30cm of light gauge wire, tie one end to the loop of the thermometer, and wind the other end around the handle of the pan so the thermometer doesn't slide down into the syrup, which should be deep enough to cover the bulb of the thermometer. Continue to boil the mixture on the highest possible heat. At this point it will seem as though the pan is much too big, but the reason for this will soon be revealed.

6. When the temperature on the sugar thermometer reaches 265°F, take the pan off the heat. With a long spoon, take out about a teaspoonful of the syrup and drop it into the iced water - after a few seconds it will have cooled enough to handle. Squeeze it flat between your thumb and forefinger, leave it in the water for a few seconds more, then remove it. Hold it between the thumb and forefingers of both hands and try to snap it. If it snaps first time, it's ready. If it just bends, return the pan to the heat, cook it a few degrees higher, then repeat the process.

7. Now that the sugar has reached the correct temperature, it's time to remove the thermometer and introduce the fat and milk mixture. Slowly pour it into the sugar syrup, stirring all the time. It will spit, so make sure you're wearing the oven mitts. It will also foam up, now and throughout the rest of the cooking, to three or four times the volume of the sugar syrup. This is why you need such a large pan. When it's all in, return the pan to a high heat and stir. After a while you'll notice small bits of brown appearing in the mixture. Don't panic! This is what gives toffee its flavour and colour - the controlled burning (caramelisation) of the sugars in the condensed milk. To avoid over-burning of any sugar, make sure that you stir continuously and that you scrape all parts of the pan - bottom, sides and corners - with the wooden spoon. The entire mixture will gradually become browner as it cooks, and when it reaches roughly the colour of milk chocolate, it should be done.

8. Remove it from the heat once more and add the butter and the vanilla. Briefly return it to the hob and stir until the butter has been incorporated - it shouldn't take more than a minute to do this. Pour the toffee into the prepared trays and leave to cool. According to the temperature you initially cook the sugar syrup to, you can make a soft, chewing toffee (lower temperature) or a hard, sucking toffee (higher temperature).

An Alternative Method

A much simpler way to make this toffee is to pour in the fat, milk and salt as soon as the glucose syrup has dissolved, and boil/stir the whole lot together. It's a perfectly good way of making toffee, and this is how it's done commercially, but as you have to cook the entire mixture to temperature, it gives you less control over the final colour of the toffee and it can be easy to break the thermometer while stirring. Mercury is not a good additive to toffee. It's also very difficult to stir while the glucose container is sitting atop the two wooden spoons without knocking them all into the pan, and you have to stir for much longer too.

Afterthoughts

When you've finished and you are (im)patiently waiting for your toffee to cool, it may seem that you have one almighty mess to clean up. Once again, don't panic. Any implement that has been used to cook sugar can be cleaned easily with boiling water. Firstly, half fill the large pan with water, put in as many of the utensils as you can fit, put a lid on it and bring it to the boil. Then, simmer it until the toffee has melted off everything. There will be some scum from the fat in the toffee, so use a regular washing-up liquid to finish the job, and rinse everything in clean, hot water.

All sugar products are hygroscopic - they attract moisture. That's why sweets go sticky if not kept in airtight containers or wrapping. The fact is, though, that this toffee probably won't last long enough to go sticky!

If you have trouble finding glucose syrup in the shops, your local baker may be able to help you out - they often use it if they make their own sugar frosting, and if you give the baker a free sample he may well like it enough to sell it in their shop.