Shepherds Pie with Portobello and Seitan

1. Cover potatoes with water 1" above potatoes and bring to a boil. While the potatoes are cooking, saute carrot, onion, and celery in oil until the onion is translucent and soft. Blend together diced tomatoes and beans.
2. Add mushroom, and saute for another 1-2 minutes. Add the stock, miso, tomato and bean puree, lentils, tomato sauce (if using), bay leaf, oregano, and thyme.
3. Add the seitan, tearing it into smaller pieces if desired. Simmer for 20-30 minutes, until the lentils are cooked through. Season to taste with salt and pepper.
4. Preheat the oven to 350 degrees F. When the potatoes are soft, drain the excess water and mash them until they are smooth with vegan butter and milk.
5. Pour/spoon the stew into a 2 quart casserole dish and drop the potatoes on top by the spoonful. With fingers or a spoon, carefully smooth the potatoes into a thick layer. If you wish, top with shredded vegan cheese. Bake 30-35 minutes.
Much more like a beef stew base than others I've tried, which tend to be heavy on the tomato and often rely on kidney beans for substance. This one approximates meaty shepherds pie much better, with the rich mushroom flavor and seitan. It's a flexible recipe.
Source of recipe: I patched this together from a variety of recipes for vegan shepherd's pie online and it turned out wonderfully.