break cauliflower into florets and soak in warm salted water for 3-4 minutes.
Drain, place in pan with hot water, cover and bring to boil. Reduce heat to simmer until florets are tender.
While cauliflower is cooking, melt butter in a pan, add flour, stir over heat heat until flour starts to bubble, remove from heat. Stir in milk, return to heat and stir until mixture boils and thickens.
Remove from heat and add cheese - let it melt into sauce.
Drain cooked cauliflower, place on serving plate and spoon cheese sauce over it. Sprinkle with Parsley. If you want you can place cauliflower in dish, top with cheese sauce and broil for a minute until sauce browns.