If using frozen broccoli, cook for about 5-6 minutes in microwave while cooking the hamburger. Brown hamburger in medium pan over med-low heat, drain. Sprinkle flour over hamburger. Add milk, stir.
In a separate bowl, stir egg and add a spoonful of meat mixture to bring the egg to the same temperature as the meat mix. Stir this back into the meat mixture. Add cream cheese to meat, cooking on med heat until smooth and creamy. You will need to stir this constantly to ensure that the cream cheese gets completely melted and mixed in. Stir in cooked broccoli. Turn heat off.
Cover bottom of square 9x9 casserole dish with 1/2 can of crescent rolls. Pour meat mixture on top. Cover meat mixture with grated mozzarella cheese. Top with the remaining crescent rolls.
Bake at 375 for 15 minutes or until rolls are golden brown and mozzarella cheese is melted.