The top is a kohlrabi. Two approaches I like a lot:
- treat it like a potato. Peel it, cut into chunks, and boil it (and optionally sliced the boiled pieces and fry them in a little butter)
- treat it like cabbage or jicama. Peel it, julienne it raw and toss with grated carrot and whatever you dress coleslaw with (mayo and lemon juice for me)
The bottom could be a very small squash or a round zucchini. You can roast, sautee, or braise (think ratatouille). If it's a zucchini you can also eat it raw.