The secret ingredient in this spin on classic chicken divan is creamy, woodsy portobello mushroom soup. Cutting the puff pastry into equal portions before baking makes serving really easy. Asparagus can replace the broccoli, if desired.
1. Preheat oven to 425°F, and place oven rack in bottom third of oven. Coat 13- x 9-inch baking dish or oval casserole or gratin dish with cooking spray.
2. Place broccoli florets in microwave-safe casserole with lid, and add 3 Tbs. water. Cover, and microwave on high power 2 minutes. Stir, cover, and microwave 2 minutes more, or until broccoli is tender. Drain, and set aside.
3. Meanwhile, whisk together soup, mayonnaise, sherry, and poultry seasoning in large bowl. Season with salt and pepper, if desired. Add seitan and broccoli florets; stir to combine. Transfer broccoli-seitan mixture to prepared baking dish, and sprinkle with Parmesan cheese, if using.
4. Cut pastry into 6 equal squares. Place squares evenly over seitan mixture. (Filling does not need to be completely covered by squares.)
5. Bake 20 minutes, or until pastry is puffed and golden and filling is hot and bubbly.