Peel the potatoes, halve them and cut them into slices approx. 5 mm thick. Peel the carrots and cut into slices approx. 5 mm thick. Roughly dice the onion and set aside. Drain the salsify well in a pasta strainer.
Bring a large pot of salted water to a boil. Carefully break the cauliflower into florets from the inside out. Break up florets that are too large. Simmer potatoes, carrots and cauliflower florets gently for 10 minutes.
Preheat the oven to 200 degrees convection.
Mix the vegetable broth and whipping cream with the spices and season well. Add the eggs and whisk well.
Grease a large baking dish with margarine. Spread the diced onion in the casserole dish with the crushed garlic and the well drained salsify. Drain the vegetables well in the pasta strainer and spread them evenly in the baking dish. Spread the prepared sauce evenly over the vegetables. Sprinkle first the grated Parmesan and then the Gouda.
Place the casserole dish in the oven for 25 minutes. Reduce the heat to about 180 degrees. Serve garnished with chives. Note: Boritz writes in the comments: Two to three pers. should be full