Boil and mash the potatoes (I leave the skins on when organic). Stir in the nutritional yeast, lemon, salt and pepper and set aside.
Preheat the oven to 425 degrees Fahrenheit.
In a cast iron or nonstick skillet heat the oil. Add the vegan sausage and cook a couple of minutes, stirring frequently.
Add the veggies and mix. Add garlic powder, onion flakes, thyme, and the paprika and tamari, if using. Mix well.
Let the veggies cook for a few minutes, stir a few times in between, until they are tender but not mushy. Add the vegetable stock and mix well.
Layer the potatoes over the top of the veggie-meat filling, then, using a spatula or spoon, mix them in.
Bake 30 minutes in the preheated oven.
Garnish, if you like, with chopped chives. Serve hot, warm or cold.