For many years, butter was eschewed in favour of other fats because they were cheaper or considered to be healthier. But butter has a wonderful flavour and richness that can't be replaced by anything else.
Types: there's unsalted and salted. It used to be that butter was salted to mask any 'off' flavours or rancidity in the milk used to make it. This isn't a common problem any more, as long as you're buying the best 'grade', which is the only type available in reputable supermarkets. You can also buy whipped butter, which spreads more easily.
Which to buy? Because the salt content varies from brand to brand, unsalted butter is best for cooking
and baking because it lets the cook determine the amount of salt added to a dish. Salted butter is best used as a spread for bread or toast. Whipped butter is convenient, but you're paying extra money for a lot of air. If you want to make it easier to spread, let the butter soften at room temperature, or you can whip it yourself with an electric beater.
Butter or margarine? Butter, of course. People used to think margarine was better for you because it's made with vegetable oil, rather than animal fat. Studies now show that hydrogenation, the process that turns oil into solid fat, is worse for you than saturated animal fat. More importantly, butter tastes better.
What else? Butter isn't 100 per cent fat; it also contains milk solids and liquid. These are what make butter sizzle, splatter and turn brown when used to saute. This brown butter adds a lot of flavour, but it can turn from brown to burned if the temperature is too high or if it's heated for too long. To slow down the browning process, use half butter and half cooking oil for sauteing. Butter can be clarified, which turns it into 100 per cent fat. Melt butter in a pan and skim off and discard the foam that floats to the surface. Pour off the golden fat (this is the clarified butter) and discard the thin, milky layer on the bottom.
Different brands of butter vary in fat content, and a higher percentage is an indication of better quality. Look on the label - it should be at least 80 per cent butterfat, preferably higher. Butter can absorb flavours from the fridge if it's stored near anything with a strong odour. It should be wrapped in aluminium foil and kept in a separate section of the fridge, or in the freezer for longer storage.
How to use: in pastries, cakes and other baked goods (see recipes, left). It's also good for sautes (see above) and sauces (such as hollandaise and bearnaise). If you 'finish' a pan gravy by swirling in a chunk of butter at the end, it adds shine and richness to the sauce.