Microwave 2 packages Broccoli Florets according to directions, drain, and place in a greased 9x13 pan.

Top the broccoli with 4 cups cooked turkey, warmed. Cover with foil to keep warm.

In a large skillet, melt 2 tablespoons butter over medium heat. Chop and saute the onion and sliced mushrooms until golden brown. Chop and add the water chestnuts. Stir in 1 cup turkey broth and bring to a boil. Reduce heat to low; simmer 3 to 5 minutes or until thickened. Add parmesan cheese; simmer one minute. Season to taste with salt & pepper; remove from heat.

Preheat broiler with rack 6 inches below. Pour sauce over turkey and broccoli. Top with the shredded cheddar and Panko crumbs. Broil until the sauce bubbles and the cheese and Panko are golden brown.