Cook shrimp on hot grill 2-3 minutes on each side until pink. Alternatively, saute shrimp in saucepan over medium heat in a non-stick frying pan coated with cooking spray. Set aside and cover to keep warm.
Cook pasta according to package instructions. Remove pasta from water by scooping out with a slotted spoon into colander. Return pasta water to stove and blanch broccoli (about 5 minutes). Strain and rinse with cold water to stop broccoli from cooking.
Melt butter in a medium saucepan over medium heat. Add garlic and cook 1 minute, stirring frequently.
Stir in flour and gradually add milk, stirring all the while with a whisk. Cook 6 minutes or until mixture thickens, stirring constantly.
Add 1 cup Parmesan cheese, cream cheese, and salt, stirring with a whisk until cheeses melt.
Toss sauce with hot pasta and broccoli.
Top with shrimp and sprinkle with remaining ¼ cup Parmesan cheese and lemon zest.