If you can’t find vegan puff pastry to use as a lid for this pot pie, use a piecrust mix to make pie dough instead. Feel free to play around with the filling and omit the seitan if you want—but whatever you use should add up to a similar amount. Try using a mixture of mushrooms and cooked root vegetables in winter, or in summer, add uncooked peas, asparagus, or broccoli to the sauce before the lid is added.