I remember as a child growing up in Green Bay going to the farmer's market and spending my allowance on any number of things. Thus typically included a kohlrabi that I ate on the walk home, skin and all. One of the neighborhood moms would peel it, slice it, and serve it to us with a little salt and pepper. Given its prominence in my formative years, I was surprised when my counterpart had never tried it.
Kohlrabi is one of those nice starchy, peppery root vegetables similar to a turnip. The name is German and loosely translates to "cabbage turnip". This is fitting as it tastes like the perfect blend of the two. It belongs to the same coniferous family as cabbage, cauliflower, and - my personal favorite - Brussel sprouts. It can be used in a similar manner in soups and sides.
It's also fairly versatile. It is more tender and less bitter than turnips, and not as forward as radishes, making it a nice choice for salads. If you want that crunchy peppery radish quality in your salad but without the pungency, kohlrabi is a good choice. The greens are also edible and provide an interesting note. A note, though, that the greens are similar to other vegetables in this family - kale, turnip, and collard greens. While not as bitter as these, there is a similar flavor and texture, so mixing with other more mild greens is recommended.
When cooked, kohlrabi has a wide range of flavors and textures, depending on how long you cook it. A quick saute slightly mutes the raw flavor, but a longer fry or oven roast brings out an unexpected sweetness. If you are using it as a side dish, having a mix of kohlrabi in various stages of the cooking process will yield a flavorful medley. It also mixes well with other roots like celeriac, turnip, and carrot.
If you're into root veggies during the cold dark winter days (and many of us seasonal eaters are), add this veg into the mix. Here are some recipe suggestions from Simply Recipes.