Slice
kohlrabi,
sweet potatoes and
onion into thin rounds. Spread olive oil over a baking dish, sprinkle with breadcrumbs and place
onion rings over it. Pre-heat oven to 200ºC and bake the
onions for about 20 minutes until they become brown. Remove from oven and place a layer of
sweet potatoes on
onions, then a layer of
kohlrabi,
sweet potatoes again, and finish with
kohlrabi. Season with salt and pepper. Pour a glass of water on the vegetables to moisten. Cover tightly with aluminium foil and bake for a further 45 minutes, until all liquid has been absorbed and vegetables have become tender.