MIX cream cheese spread, lemon zest, juice and garlic powder until blended.
MELT butter in medium saucepan on medium heat. Add onions; cook 4 min. or until crisp-tender, stirring frequently. Stir in flour; cook and stir 1 min.
ADD broth gradually, then milk, stirring constantly until blended. Stir in broccoli; bring to boil. Simmer on medium-low heat 5 min. or until soup is heated through. Add, in batches, to blender; blend until smooth. Return to saucepan. Stir in pepper. Whisk in cream cheese mixture; simmer 2 to 3 min. until heated through, stirring constantly.