Preheat the oven to 350F. Trim the leaves and coarse stems from the broccoli. Cut the remaining stems and florets into bite-size pieces. Bring about 1 inch of lightly salted water to boiling in a 2-quart saucepan. Add the broccoli and boil, covered, until crisp-tender, about 5 minutes. Drain thoroughly in a colander, then transfer to an ungreased 1 quart casserole or an 8x8x2-inch baking dish.

Meanwhile, melt the butter in a 1-quart saucepan over medium heat. Add the onion and cook, uncovered, until soft, about 5 minutes. Blend in the flour, salt and pepper, and the poultry seasoning if used, to make a smooth paste. Gradually add the milk and cook over medium heat, stirring, until thickened, about 5 minutes.

Add the chicken to the sauce, then pour the mixture over the broccoli. Sprinkle the cheese over the top of the casserole. Bake, uncovered, for 15 minutes.

[ Reader's Digest Quick, Thrifty Cooking; 1985 ]