Bring 400ml of vegetable stock to the boil in a pan. Peel and crush the garlic. Add the rice to the pan, cover and cook over low heat for about 25 minutes.
Meanwhile wash and peel the kohlrabi and carrots. Cut the kohlrabi into eighths. Cut the carrots and kohlrabi into 5mm thick slices.
Wash the broccoli and divide into florets. Peel the stalk and cut it into 5mm thick slices.
In a pan, bring the remaining vegetable stock to the boil. Add the carrots and kohlrabi and cook over a medium heat for about 2 minutes. Add the broccoli and cook for another 5 minutes.
Drain the vegetables , reserving the stock.
Tip the rice into an ovenproof dish and spread level. Add the vegetables and spread them out evenly.
Beat the eggs, add to the stock and mix. Season with salt, pepper and nutmeg.
Pour the liquid over the vegetables and sprinkle with Gouda. Cook the casserole in a preheated oven at 200°C (fan 180°C, gas 6).
Wash and finely chop the chives. Mix with the yogurt, salt and chilli powder and serve with the casserole.