HEAT oven to 350°F.
LAYER half each of the macaroni, Velveeta and cheddar in 13x9-inch baking dish sprayed with cooking spray. Whisk egg and milk until blended; pour half over ingredients in baking dish. Repeat with remaining macaroni, Velveeta, cheddar and milk mixture.
SPRINKLE with paprika.
BAKE 30 min. or until macaroni mixture is heated through and top is golden brown, stirring after 30 min.
serving size = 1 cup (250 mL)