Peel and wash the prawns. Wash broccoli. Then peel the stalk and cut into cubes. Cut the green tips from the broccoli florets and set aside. Divide the remaining broccoli into florets, halve the large florets.
Melt the butter in a saucepan and sauté the broccoli in it. Add the stock and cook the broccoli very soft, then puree. Add milk (and / or cream). Bring to the boil and add the spices. Mix the flour with a little cold water. Then stir in and beat with a whisk if possible to avoid lumps.
Add the broccoli florets and let simmer for another 10 minutes. Add the prawns for the last 5 minutes and let them cook through.