Preheat the oven to 350 degrees F
Heat the oil. Add the garlic to it, saute for a few seconds, then add the meatless meat. Saute over medium-high heat until it begins to brown, about three minutes.
Add the potatoes to the skillet and continue to cook, stirring frequently, for another five minutes.
Add the cabbage to the skillet along with the thyme, sage and salt and ground black pepper to taste. Add the soy sauce, if using, and tomato paste and stir it in. Stir, cover, and cook the cabbage for about 5-8 minutes or until it's cooked down a bit but still has a bite.
Turn off the heat and ladle the cabbage-sausage-potato mixture into a greased, 9 X 12 inch baking dish.
Ladle the cream of mushroom soup over the cabbage mixture, spreading it evenly.
Sprinkle the vegan cheese on top. Place the casserole in the oven and bake 35 minutes.
At the end of cooking you can turn on the broiler for a couple of minutes if you want to cheese to melt a bit further and brown. This is optional.
Remove the casserole from the oven and let it stand about 10-15 minutes. Sprinkle on the scallions before serving.