1. Preheat oven to 400 degrees.  Butter a shallow casserole dish.  Bring a large saucepan of salted water to bowl for the broccoli and cook until tender.  Drain, cool under running water.  Be sure it is dry before adding to bowl later on with the cooked chicken.

2. Melt 4 tablespoons butter in a large saucepan over medium heat.  When the butter is melted, add the sage and let it sizzle a minute, then add the flour.  Cook the roux, whisking continuously for 2 to 3 minutes.  Do not let it get brown.  Pour in the sherry (or broth) and cook until redued, about 1 minute.

3. Whisk in the other amount of broth, the milk, and the heavy cream.  Add the nutmeg and season with salt and pepper.  Bring to a simmer and cook whisking occasionally to get out the lumps, until thickened, about 6 minutes.  Stir in the scallions, and gruyere cheese until the cheese is melted. Remove the sauce from the heat.

4. In a large bowl, mix together the sauce, broccoli, cooked chicken, and almonds until all is thoroughly coated with the sauce.  Pour into a casserole dish.  In a small bowl, melt the remaining tablespoon of butter in the microwave.  Toss the paremsan cheese and the breadcrumbs into the melted butter.  Sprinkle over the top of the casserole.

5. Bake until golden brown, about 35 minutes.