what to do with kohlrabi?

Its also good roasted, simply with olive oil and seasoning, like a potato. What a great veggie, its so versatile.

You can go raw or cooked - I like mine julienned in slaws or stir fried

I made a really tasty Chinese-style slaw with kohlrabi using a recipe from the Joy of Cooking:

2 kohlrabi
3 tablespoons salt
2 tablespoons minced garlic
2 tablespoons red pepper flakes
1 tablespoon sugar
1 tablespoon rice wine vinegar
1 1/2 tablespoons olive oil
2 tablespoons toasted sesame oil

Peel kohlrabi and slice into 2 inch matchsticks. Place in a large bowl and toss with salt, then let the mixture sit for 45 minutes to drain. Remove all accumulated liquid and rinse well, then add the rest of the ingredients and stir to combine. Add salt to taste and let marinate for at least one hour before serving.

This slaw is insanely delicious. And quite spicy, if I recall correctly.

Here's a bunch of ideas to get you started: http://food52.com/recipes/search?c=1&recipe_search=kohlrabi