Cauliflower Augratin (Point-less Meals)

This recipe is from http://pointlessmeals.blogspot.com/2011/01/cauliflower-augratin.html

I made this for dinner tonight and it was yummy! I only used a head of cauliflower 
and then half the recipe. I did add extra salt. :)
serves 12 ( 4 points + )

3 pkgs. ( 16 oz each ) frozen cauliflower
1 large onion, chopped
⅓ c. butter, cubed
⅓ c. flour
½ tsp. salt
¼ tsp. ground mustard
¼ tsp. pepper
2 c. skim milk
½ c. grated Parmesan cheese

Topping:
½ c. whole wheat soft bread crumbs
2 T. butter, melted
¼ tsp. paprika

Cook cauliflower in a Dutch oven with a little water; drain.
Place cauliflower in the bottom of a 13 x 9 dish coated with cooking spray.
Meanwhile, in a large saucepan, melt butter. Add onions and cook until tender. 
Stir in flour, mustard, salt and pepper. Gradually add milk, stirring and cooking until thickened. Remove from heat; add Parmesan cheese. Stir until blended.
Spread cheese mixture over cauliflower.
Mix bread crumbs with butter and paprika. Sprinkle over cheese mixture. 
Bake, uncovered, at 350 for 30-35 minutes.