PREPARE pasta according to package directions; drain, reserving 1 cup cooking water. MELT butter in large saucepan over medium heat. Add garlic; cook for 1 minute or until fragrant. Stir in flour; cook, stirring constantly, for 1 minute. SLOWLY whisk in milk and ½ cup reserved water. Cook, whisking frequently, until thickened. Season with salt and pepper. Stir in cheese until melted. Add pasta and parsley to saucepan; toss to coat. Loosen with remaining reserved water if needed.