Nutmeg is a spice that is used sparingly. Many recipes call for just a few "scrapes" or "grinds" of it because its flavour and aroma are so pervasive. Once it's ground, those dissipate quickly, so it's better to buy whole nutmeg (which keep for a long time) and grate it just before use (there are special nutmeg graters, but a Microplane also works well).
The nutmeg isn't actually a nut; rather, it's the hard seed of a fruit. It's covered by a delicate, reddish-orange, web-like mace, which is also used as a spice. The nutmeg tree is indigenous to the Banda Islands of Indonesia, although it's now also grown in other places.
Nutmeg can be steamed and distilled to produce essential oil, which is used to help digestive problems, stimulate the appetite and act as an anti-inflammatory. A high dose of it can be hallucinogenic and/or toxic.
The spice is used in sweet and savoury dishes. It's especially good with dishes that include egg, cheese and/or cream, such as bechamel sauce, eggnog, custard and vegetable cream soups. It's used in certain types of spice mixtures, such as quatre epices.
I love it in a dish of creamed spinach. Make a bechamel sauce by melting some butter in a saucepan. Add flour - an amount that's equal to the weight of the butter - and stir constantly over a low flame for about two minutes. Whisk in hot milk a little at a time to create a thick but pourable sauce. Season the mixture with salt and a few gratings of nutmeg, then cook over a low flame for about three minutes, stirring often. Heat a large pot of lightly salted boiling water and blanch well-washed spinach leaves. When the spinach is wilted, drain it thoroughly. Roll the spinach in a clean kitchen cloth and squeeze out as much water as possible. Roughly chop the spinach and mix it with enough bechamel sauce to thoroughly coat the vegetable. Spread the mixture in a gratin dish, sprinkle with freshly grated parmesan cheese and bake at 200 degrees Celsius for 10 minutes, or until it's hot and bubbling and the surface is lightly browned.