CHICKEN SPINACH CASSEROLE WITH MUSHROOMS AND PHYLLO

Chicken Spinach Casserole with Mushrooms and Phyllo image

Provided by Tara Bench

Time 1h

Yield 6 servings

Number Of Ingredients 12

4 tablespoons unsalted butter
1 tablespoon olive oil
1 small onion, chopped
4 ounces shiitake mushrooms, trimmed and thinly sliced
Kosher salt
5 ounces baby spinach
3 cups diced cooked chicken (from 1 rotisserie chicken)
1/3 cup all-purpose flour
2 1/4 cups low-sodium chicken broth
1 tablespoon fresh lemon juice
1 tablespoon coarsely chopped fresh rosemary
8 sheets frozen phyllo dough (9-by-13-inch sheets), thawed according to the package?s instructions

Steps:

Preheat the oven to 400 degrees F.
Melt 1 tablespoon of the butter with the olive oil in a large nonstick skillet over medium-high heat, then add the onions. Cook, stirring, until just soft, about 4 minutes. Add the mushrooms and 1/2 teaspoon salt and continue stirring until softened, about 4 minutes. Gradually add the spinach and stir until completely wilted, about 2 minutes. Transfer to a large bowl and add the chicken; wipe the skillet clean.
Whisk together the flour, broth, lemon juice and 1/2 teaspoon salt and add to the same skillet over medium-high heat. Whisk until the mixture is boiling and simmer until just thick, about 2 minutes. Add to the chicken mixture with 1/2 tablespoon of the rosemary, then transfer to a 2-quart baking dish.
Melt the remaining 3 tablespoons butter and brush onto each phyllo sheet, layering one on top of the other. Gently place over the baking dish and crimp the sides to fit. Sprinkle with the remaining 1/2 tablespoon rosemary and bake until golden, 25 to 30 minutes. Let cool slightly before serving.