Clean the cauliflower, cut into florets and wash. In a large pot, boil up plenty of salted water with milk and lemon juice. Add the cauliflower and cook for 10-12 minutes
Peel and finely chop the onion. Heat butter in a pot. Sauté the onion in it, season with a little salt, remove from the heat and let it cool down. Wash the dill, shake dry, pluck and chop all but a little of the dill from the stalks. Mix the dill and prawns with the onion in the pot. Lift the cauliflower out of the water, arrange with the crabs and salmon caviar, garnish with dill