½cup4 oz Boursin Light Garlic and Herbs Spreadable cheese
⅓cuppanko bread crumbs
Heat oven to 425°F. Spread cauliflower on a rimmed baking sheet and coat lightly with cooking spray. Roast until florets begin to brown, about 10 min. Remove cauliflower and reduce oven to 375°F.
Cook pasta according to package instructions, drain and set aside. In a large saucepan over medium heat whisk olive oil and flour for 1 min. Add milk, whisking constantly. Stir in mustard, salt and cayenne. Cook, stirring occasionally until mixture has thickened, about 8 min. Remove sauce from heat. Add 2 cups cheddar, Parmesan and Boursin and stir until melted. Add pasta and cauliflower; stir to coat.
Pour pasta into a greased 2-qt baking dish. Sprinkle on ½ cup cheddar, then bread crumbs. Bake until bread crumbs are golden brown and cheese is bubbling, about 30 min.