Peel the carrots, cut in half lengthways and cut into slices. Clean the cauliflower and cut into florets. Cut the leek into slices and wash. Clean and halve the mushrooms.
Bring the broth to a boil. Let the carrots and cauliflower cook for 5 minutes. Add the leek and cook for another 5 minutes. Drain and collect the broth.
Heat the butter in a pan and fry the mushrooms while turning.
Melt 30 g butter in a saucepan, add 30 g flour, sweat until golden yellow, deglaze with cream and, if necessary, with the vegetable stock to create a creamy sauce. Bring to the boil, stir in the Gouda and season with salt and pepper. Add the herbs.
Put the vegetables and mushrooms in a baking dish and pour the sauce over them.
Peel and roughly grate the potatoes. Mix with egg, salt, pepper and nutmeg. Spread the potato mixture on the vegetables and bake in the preheated oven at 200 ° C for about 30 minutes.