Take the puff pastry package out of the freezer 45 minutes before you are ready to roll it out. Preheat the oven to 400° F (204° C).
Peel and dice 3 cups of potatoes into small bite-sized pieces and set them aside along with 2 cups of chicken seitan or your faux chicken of choice.
Peel and dice a small onion and 2-3 cloves of garlic. Sauté them over low heat in 3 tablespoons of light olive oil in a large skillet (oven-safe skillet if possible) and sprinkle them with salt and poultry seasoning.
Add 3 cups of frozen mixed veggies to the skillet and cook for another 3 minutes.
Sprinkle the cooked veggies with 5 tablespoons of flour and mix well.
Turn up the heat to medium-low and slowly add 2 cups of vegetable broth 1/2 cup at a time until the broth is creamy and smooth. Sprinkle in 1 tablespoon of nutritional yeast (optional).
Add 1 cup of plain plant-based milk and stir well. Then add the diced potatoes and 2 cups of faux vegan chicken and stir well.
Use a rolling pin to lightly roll out a piece of puff pastry so that it is large enough to fit over your pot pie and cut it with a sharp knife into the shape that you need. Place it directly over the pot pie filling and poke a few holes in it with a sharp knife or fork. (If your skillet is not oven-safe, transfer it to a baking dish before topping with the pastry puff.)
Bake your pot pie at 400° F (204° C) for about 20 minutes until the pastry has puffed up and the top is golden brown.
Allow cooling for about 10 minutes before serving.
Notes
If you forget to thaw your puff pastry in time you can wrap it in a paper towel, and pop it in the microwave for 20 seconds, flip it and microwave it for another 15 seconds, then open it up and microwave it for an additional 15 seconds.
Measure your puff pastry with the lid of your pan for a perfect fit or simply cover the top and trim off the edges.
Be sure to cut the potatoes into small bite-sized pieces so they cook completely while baking in the oven.
For a lower sodium pot pie reduce or omit the salt.