Preheat oven to 400 degrees. Place dough on a floured work surface. Using a lightly floured rolling pin, roll out to 1/8-inch thick rectangle about 9 by 12 inches. Place on a parchment-lined baking sheet and brush with the egg wash. Bake for 17 to 22 minutes, until golden brown. Let cool for 5 minutes.
For the filling: Meanwhile, melt 4 tablespoons butter in a 12-inch skillet over medium heat. Add onion and cook, stirring, just until tender, about 5 minutes. Add the 1/3 cup flour, 1/2 teaspoon thyme, 1/4 teaspoon salt and 1/4 teaspoon pepper and cook, stirring, for 1 minute. Whisk in the chicken broth and bring to a boil. Reduce the heat to low and simmer, stirring occasionally, until slightly thickened, about 3 to 4 minutes.
Stir in the sweet potatoes and simmer, stirring occasionally, for 10 to 15 minutes, or until the sweet potatoes are just tender. Stir in the chicken, Swiss chard and cream, increase heat to medium and return to a simmer. Cook, stirring, for 2 to 3 minutes, until Swiss chard is wilted. Remove from heat. Taste and re-season if necessary. Let stand for 5 minutes.
Break the crust into large pieces, about the size of your palm, and arrange on top of the hot filling, and serve.
Nutrition information per serving:
Calories630Fat38 gSodium540 mg