The skin is edible, although larger eggplants can be a little tough. If your eggplant is young, tender, and on the small side, the nutrient-rich skin can probably be left on for skillet frying or braising. Otherwise, peel the skin and then slice or cube the flesh.
The flesh should be pale and creamy and free of blemishes. Remove dark or bruised portions and seeds that are turning brown, as they can have a bitter taste and an unpleasant texture.
If you’re roasting the eggplant whole in the oven or on the grill, leave the skin on, then after roasting, let it cool, and scoop out the flesh.
To Salt or Not to Salt
This is a much debated topic. Salting your eggplant slices or cubes does have a few things going for it. First, it draws out juices, which, particularly for older eggplants, can be bitter. It also tightens and firms up the flesh, making the eggplant less likely to soak up as much oil. And salt adds flavor.
However, many cooks point out that modern varieties are not the bitter fruits of the past and that salting them makes little difference. Varieties like Japanese and Chinese eggplant should be fine without salting. With globe eggplants, experiment for yourself.
If you choose to salt your eggplant, first slice or cube it, and then salt generously, allowing the fruit to sit in a colander for at least an hour, preferably longer. Salted eggplant can sit purging for hours without harming the taste or texture. But before cooking the eggplant, be sure to rinse the salt off well. Then place the slices between sheets of paper towel and press gently to remove juices and firm the flesh. This is particularly important when frying your eggplant slices or cubes.