Heat potatoes according to package directions. Keep warm.
Cook cauliflower in boiling water 7 minutes or until tender. Drain.
Place fat-free milk, garlic cloves, and bay leaf in a small saucepan; bring to a simmer. Cover and cook over low heat for 10 minutes. Discard bay leaf. Place cauliflower, milk mixture, butter, and salt in a food processor, and process until smooth, scraping sides of the bowl occasionally. Combine mashed potatoes and cauliflower mixture in a large bowl, stirring until well blended.