Directions
1.    Preheat oven to 350 degrees F. Coat a 9-inch glass or ceramic baking dish with cooking spray.
2.    Bring a large saucepan of water to a boil. Trim cauliflower and break into small florets. Boil until tender, 10-15 minutes. Drain. Place in a blender or processor with 1/2 cup milk and puree until thick and smooth. Set aside.
3.    Cook pasta according to directions until al dente.
4.    For the sauce, melt 2 tablespoons Smart Balance in a medium saucepan over medium heat. Add flour and whisk briskly. Gradually add 2 cups milk, whisking continuously, until it reaches a boil. Reduce heat and simmer for 3 minutes, or until thick and bubbly. Add the pureed cauliflower, 1 cup cheddar cheese, and a generous amount of salt and black pepper. Whisk until smooth and remove from heat. Add cooked pasta to the cheese sauce and toss until well coated. Pour into the prepared baking dish and sprinkle remaining 1/2 cup cheddar evenly over the top.
5.    For the buttered breadcrumbs, melt 1 tablespoon Smart Balance butter substitute in a small skillet over medium heat. Add bread crumbs and toss until coated with butter. Sprinkle even over the top of the cheddar. Or, if you prefer, set crumbs aside, and use as a garnish just before serving.
6.    Bake for 40-45 minutes or until golden brown on top and the cheese sauce is bubbling around the edges.