Kohlrabi is a member of the cruciferous (cabbage) family;
the stem just above the soil swells to a fat little round, with leafy green tops.
The tops are edible - they are very cabbage-y - and can be cooked in the manner of any tough green. The bulb itself is great RAW (YUM) or cooked.
Quick Kohlrabi Pickles
2-4 small kohlrabi bulbs, trimmed, peeled, and cut into 1/2" cubes
Organic olive oil (optional)
Fresh Black Pepper
Place the kohlrabi chunks in the bowl of a lidded, airtight container. Drizzle with a touch of olive oil, a good splash of vinegar, and sprinkle liberally with salt and pepper. Replace the lid and shake well. Taste and adjust seasoning. Place in fridge, shaking occasionally. They are best after they have marinated for a few hours, and will last about a week, becoming more intensely flavored but still largely retaining their lovely texture.