The beep test
A lot of passionate cooks disdain the microwave. I don't use mine on a daily basis but I'm glad it's there.
I use it for reheating food and only rarely to cook raw ingredients: microwaved chicken doesn't brown and steamed fish goes from undercooked to overcooked in seconds. However, I'm beginning to rethink my ban on microwave 'baking' after being served the lightest sponge cake at Spain's El Bulli restaurant. The batter was siphoned into paper cups before being microwaved for about 15 seconds. It didn't have the appetising crust of a baked cake but the texture, partly from the air introduced by the siphon, was amazing.
The microwave is my favourite tool for melting chocolate. There are too many drawbacks to the traditional double boiler: the chocolate will scorch if the water in the bottom boiler is too hot and 'seize' or harden if any water gets into the top bowl. With a microwave, there's no moisture to worry about. Chocolate maintains its shape in the microwave, even as it's melting, so to make sure it doesn't burn it should be stirred every 30 seconds, until it's half melted, and every 10 seconds after that. Remove it from the microwave when it is 90 per cent melted and stir as the residual heat melts the rest. Use the same method for melting butter, but lay a paper towel over the bowl to catch any splatters.
A microwave is great for heating braises and stews because the ingredients are already cooked, although you may need to add more liquid.
I rarely use the microwave to thaw meat, however, because, even on the defrost setting, I've found it starts to cook. Better to wrap the meat in a double layer of cling-film and thaw in hot, but not scalding, water. A thick steak will defrost in less than 30 minutes using this method.