COOK onion and garlic in butter in large saucepan on medium-high heat until tender, stirring frequently. Add flour; mix well. Cook 2 min. or until hot and bubbly, stirring frequently.
STIR in milk until well blended. Cook until mixture boils and thickens, sitrring constantly. Reduce heat to low; simmer 5 min., stirring occasionally.
ADD remaining ingredients; mix well. Cook 5 min. or until VELVEETA is completely melted and soup is heated through, stirring constantly.