Preheat the oven to 425 degrees F.
Place cauliflower florets on a microwave-safe plate and cover with wet paper towel.
Microwave on high for about four minutes, until crisp-tender.
Place the cauliflower in a single layer into an 8x8 inch baking dish.
Melt the butter in a small sauce pan over medium heat.
Add flour and whisk until it makes a bubbly paste.
Gradually add the milk and stir until the sauce becomes thick and creamy.
Remove from heat and add salt, pepper, nutmeg and half of the sharp cheese. (Do not add the parmesan yet.)
Spoon the sauce over the cauliflower florets and sprinkle with remaining sharp cheese as well as the parmesan.
Bake for 15 to 20 minutes until the cheese sauce is soft and slightly golden.
As written, this recipe serves 4 as a side dish or 2 as a main course.