We successfully grow both purple and green/white kohlrabi in the field, and have taken a liking to this oddly shaped vegetable! The taste we describe is like an apple'y cabbage? You can eat the bulb and the leaves too.
Remove the leaves and thinly slice, grate or chop in a blender to add to salad or coleslaw for an incredible crunch and hit of vibrant colour.
Boil, roast or add to a stir fry too! Cook the leaves as you would cabbage.