This would go well on IceCream or BrowniesFromScratch or possibly other foods.

1. Prepare equipment. You need to lightly rub a big baking sheet with a lightly-flavored oil, obtain a small dish of water and something like a brush to manipulate that water with, put a heavy-bottomed pot on the stove, and put on shoes. Never cook sugar syrups without enclosed shoes on.
2. Prepare ingredients. Measure 3/4 c white sugar into a heap in the middle of your heavy-bottomed pot (brown sugar or a too-light pot will lead to unpleasant burning in your candy). Pour 1/8 c water and a teaspoon or so of lemon juice around the edge (don't let it hit and scatter the sugar). You may remember this trick from CaramelSauce if you've read that. Optionally, measure out and set aside up to a teaspoon of good salt, like sea salt or kosher salt. As I said about MoroccanStylePreservedLemon, forget about the ordinary kitchen salt, it's too harsh after they add all the iodine and anti-caking junk and fiber and MSG and artificial salt flavoring and preservatives and dyes and plant food and crap to it. Anyway, a full teaspoon of kosher salt will make a very distinctly salty toffee, or a lesser proportion will be subtler.
3. Cook. Turn the heat up high. Stir the water into the sugar (goal: no sugar grains on the walls of the pot) and continue stirring until all of a sudden the solid grains will disappear and you'll have only a clear syrup. Stop stirring, get that spoon out of there, and just let the syrup cook (you can swirl it, just no tools). Periodically brush water around the wall of the pot near the surface of the syrup to prevent spatters from drying into crystals. The syrup will become golden, then reddish, then start to tinge brown and smell burnt. At the dark red stage or (at the latest) the first trace of burnt smell, the toffee is cooked. Throw in the salt if using, and immediately pour the syrup into one end of the oiled pan and tilt it (dramatically!) so it spreads thinly down.
4. Remove. Set pan down somewhere and let it cool. Crack the toffee to desired size with a knife and use.