Preheat oven to 375 degrees.
Prepare Magic Chicken ahead of time.
Steam broccoli, drain, put into a 9 x 13 pan.
Spread cubed Magic Chicken over broccoli.
Melt 2 TBSP butter in a saucepan, add flour to make a roux. Stir until it thickens.
Add broth, cook until it thickens, stirring constantly.
Remove from heat, add mayo and lemon juice.
Spread over chicken.
Sprinkle cheese over mixture.
Melt 2 TBSP butter, stir in bread crumbs. Sprinkle over cheese.
Bake for 35 minutes at 375 degrees.