Skillet Macaroni and Cheese with Tomatoes

Whisk milk and cornstarch in a medium-size nonstick saucepan until blended. Bring to a boil over medium heat, stirring often. Stir in mustard, salt and hot pepper sauce until blended. Reduce heat to medium-low and simmer uncovered 1 minute or until thickened. Stir in cheese until melted. Stir in macaroni, tomatoes and scallions and heat through.