Preheat oven to 375°F. 

Prepare pasta according to package directions, reducing cooking time by one-third; drain.

While pasta is cooking, combine milk and ricotta in a blender and blend until smooth. Transfer to a medium mixing bowl and stir in cheddar cheese, ⅓ cup of Parmesan cheese, parsley and salt and pepper.

Stir pasta into cheese mixture until well blended.

Transfer to a 10-inch round casserole dish.

Stir bread crumbs, margarine and remaining 2 tablespoons of Parmesan cheese in a small bowl until thoroughly mixed. Sprinkle mixture evenly over casserole.

Bake at 375°F until heated through, bubbling around the edges, and bread crumbs are golden brown, about 35 minutes. Serve immediately.

Source: National Pasta Association