Chicken Divan Revisted

This is not your grandma's chicken divan... 

Not that there's anything wrong with her recipe!  But it probably has a lot of butter and cheese and mayo, so I tweaked a little bit, and with the help of the Internet, here's what I came up with.  This one's freezer-friendly, and you can use a rotisserie chicken, leftover turkey from Thanksgiving, or whatever you have on hand.  If you chop up the broccoli a little smaller, then kids tend to eat it a little better than if you've got big ol' trees in there.  I like to cook a giant package of chicken breasts and then freeze the meat (cut up) to throw in recipes.  Anyway, I'm getting off track.  Here's Chicken Divan, revisited:

Light(er) Chicken Divan

1 1/2 pounds boneless, skinless chicken breast, cooked and cut into bite-sized pieces (or turkey!)
1 tablespoon extra-virgin olive oil
2 cups diced leek, white and light green parts only (see Tip), or white onion - then use 1 to 1-1/2 cups
1/2 teaspoon salt
5 tablespoons all-purpose flour
1 14-ounce can reduced-sodium chicken broth
1 cup low-fat milk
2 tablespoons dry sherry (from the wine section, not the cooking sherry)
1/2 teaspoon dried thyme
1/2 teaspoon freshly ground pepper
1 lb. broccoli crowns, chopped (could use frozen, thawed, too)
1 c. Parmesan cheese, grated (or Asiago), separated
1/4 cup low-fat mayonnaise (I prefer Hellmann's)
3-4 teaspoons Dijon mustard (I'm a big fan of the Dijon)

Coat a 7-by-11-inch (2-quart)  glass baking dish with cooking spray (a 9x13 will work if that's what you've got).  Place chicken in a medium skillet or saucepan and add water to cover. Bring to a simmer over high heat.

Heat oil in a large nonstick skillet over medium-high heat. Add leek and salt and cook, stirring often, until softened but not browned, 3 to 4 minutes. Add flour; stir to coat (cook about 2 minutes to remove the raw flour taste). Add broth, milk, sherry, thyme and pepper and bring to a simmer, stirring constantly. Add broccoli; return to a simmer. Remove from heat and stir in 1/2 cup Parmesan or Asiago, mayonnaise and mustard.

Spread half the broccoli mixture in the prepared baking dish. Top with the chicken, then the remaining broccoli mixture. Sprinkle evenly with the remaining 1/2 cup of cheese.  Let cool completely, then wrap in foil and freeze.  Thaw in the fridge, then bake, uncovered in a 375°F oven. Bake until bubbling, 20 to 25 minutes. Let cool for 10 minutes before serving.

Tip: To clean leeks, trim and discard green tops and white roots. Split leeks lengthwise and place in plenty of water. Swish the leeks in the water to release any sand or soil. Drain. Repeat until no grit remains.