1 large bunch broccoli, cut into bite size pieces
5 TBS butter
3 TBS flour 
2 cups chicken broth
1 shallot, thinly diced
3 TBS sherry ( I use cream sherry)
salt and pepper
1 TBS lemon juice
1/2 cup sour cream
1/2 cup grated Parmesan cheese
1~1/2 lbs. cooked chicken breast, shredded
1 cup dry breadcrumbs

Preheat oven to 350 degrees.

Cook the broccoli in salted water for 4-5 minutes and stop cooking with an ice bath. Drain and set aside.

In a large skillet, melt 3TBS butter and add flour. Cook for a couple of minutes. Add broth and whisk. Bring to a boil and then turn back heat and simmer until thickens, about 10 minutes.
Add sherry, salt and pepper, lemon juice, sour cream and 1/4 cup Parmesan Cheese.

Put the broccoli in the bottom of a flame proof baking dish. Pour over 1/2 of the sauce over the broccoli and top with the chicken. Pour sauce over the chicken. 
Wipe out sauce pan and melt the final 2 TBS butter. Take butter off the heat. Add breadcrumbs and mix together. Add remaining cheese and mix.
Spoon on top of the sauce.
Bake for 30 minutes until heated through. Put under the broiler until the breadcrumb mixture is golden brown.