Potato Casserole

Adapted from recipezaar.com

1-1/4 cups water
1 cup soy milk
3/4 cup nutritional yeast
3 tablespoons cornstarch
1 tablespoon lemon juice
1/2 teaspoon garlic powder
1 teaspoon onion powder
1 tablespoon ground mustard
1/2 teaspoon paprika
1 pinch cayenne
2 tablespoons tahini
2 teaspoons white miso
2 teaspoons dried parsley
1/4 teaspoon liquid smoke

potatoes, sliced thin
celery, chopped fairly fine
seitan, chopped
ground pepper

Preheat oven to 400 degrees. Oil a large 3-quart casserole. In a blender, place all sauce ingredients and mix well. Place a layer of half of the sliced potatoes in casserole. Sprinkle celery over potatoes, then add the seitan. Cover with the remaining potatoes. Pour the sauce over the top and sprinkle with ground pepper. Cover tightly with foil and bake at 400 degrees for 45 minutes. Remove foil and bake another 15-20 minutes until potatoes are tender and sauce is thickened. Remove from oven and let stand a few minutes before serving.