How to Boil the Cauliflower:

1. Bring a large pot of water to boil, place cauliflower in the boiling water, completely covered, and boil the whole head for about 15 minutes, flowerets 3-6 minutes or until cooked to your taste. Do not overcook. Drain and chop into finely cut pieces.

How to steam cauliflower:

1. Grab a large soup pot and fill the bottom with 2-inches of water. Place the steamer in the pot and then the cauliflower. Cover with a lid. Steam the cauliflower for 5-7 minutes. Drain and chop into finely cut pieces.

1. Preheat the oven to (350°F) = (176°C) degrees.

2. Grease a 9 by 13-inch baking pan and set aside.

3. Melt the butter in a large saucepan, add the flour and whisk immediately. This is called a roux.

4. Add the milk to the roux stirring constantly and cook until the mixture is thick and smooth.

5. Add the salt, pepper, the dry mustard and continue stirring.

6. Add 2-1/2 cups of the shredded/grated cheese reserving 1/2 cup to top the casserole before baking.

7. Keep stirring until the cheese has melted and the mixture is smooth. Combine the cooked cauliflower and the cheese mixture and stir until mixed.

3. Pour into the greased 9 by 13 baking pan. Sprinkle the remaining 1/2 cup of cheese on top. Bake uncovered for 30 minutes or until cooked through.