Wash the broccoli and cut into florets. Peel the stem and cut into sticks. Leave out the butter and sauté the broccoli for approx. 2-3 minutes. Add the water and continue cooking for about 5-6 minutes. Then drain and save the cooking water for the sauce. Put the vegetables in a greased baking dish.
Make a roux from the fat, flour, the cooking water and milk. Bring to the boil briefly. Stir in the processed cheese. Let it warm up and pour everything over the broccoli.
Bake in a preheated oven at 180 ° C for about 20 minutes. Serve hot.