Preheat oven to 375F. Parboil onions in salted water 10 to 12 minutes. Cook broccoli according to package directions. Drain onions and broccoli. Place onion in baking dish and remove center of onions, leaving 3/4-inch edges.
Chop onion centers, combine with broccoli, Parmesan cheese, mayonnaise and lemon juice. Spoon into onion shells. In a saucepan over medium heat, melt butter.
Blend in flour, salt pepper and milk. Cook until thick, stirring constantly Remove from heat. Blend in cream cheese. Spoon over stuffed onions. Bake uncovered 20 minutes.
Cajun Country -- New Iberia, Louisiana