Press water out of tofu blocks using a tofu press or alternative method, then slice blocks sideways and lengthwise into 4-5 planks, and then cut planks into 1/2” cubes.
Boil whole potatoes or steam until soft and easily pierced with a fork. Drain water and mash potatoes thoroughly by hand, or using a mixer, until smooth and all lumps are removed, adding vegetable broth as needed. The mashed potatoes should be able to spread easily over the pie. Cover and set aside.
Preheat oven to 350.
Add 1/3 cup vegetable broth to a non-stick sauté pan, then sauté onions and mushrooms over medium-high heat until onions are semi-translucent, replenishing vegetable broth and deglazing pan as needed.
Add salt, pepper, and seasonings. Add remainder of vegetables and sauté for about 5 minutes, or until al dente. When finished, add cooked vegetables to the deep dish pan.
Add 1/2 cup of vegetable broth to the same non-stick pan over medium-high heat until bubbling. Add tofu cubes and sauté until browned, replenishing vegetable broth and deglazing pan as the broth evaporates.
When browned, add tofu cubes and toss with the cooked vegetables.
Add 4 cups water to the same non-stick sauté pan, then add 3 Not-Chick’n Cubes to water, add arrowroot powder or cornstarch, and bring to a boil for 5 minutes to reduce a bit. Add this broth to the deep dish pan.
Add additional salt and pepper to taste. Spread mashed potatoes evenly over the vegetable broth mixture. Mashed potato layer should be at least 1-inch thick.
Bake mixture uncovered for one hour.
If desired, set oven to broil or increase oven temperature to 450 degrees for 10 minutes to crisp the top of the mashed potatoes.