Cornmeal and masa are not the same thing. Masa is ground from nixtamalized corn, which has been treated with lime to remove the skins from the corn kernels. It also converts the niacin in the corn to a form that can be digested by the body.
Also, tamales have some sort of filling inside the masa. It can be made of cooked, shredded meat or vegetables.
Tamale pie goes by different names, depending on who's making it, i.e. enchilada pie, Mexican Lasagna, tamale pie - all the same thing. It can be made with masa Harina, but is also frequently made using fresh corn tortillas. And yes, it would work very nicely with TVP (textured vegetable protein, usually soy), or Wheat protein (seitan0. Be careful with it the TVP as it does have its own flavor, though it absorbs the flavors of the foods it is paired with.
Chief's Tamale Pie
This is my own version of this popular 70's/80's recipe. It comes out very flavorful. The only caveat is that it contains cheese, and I don't know if you consume cheese or not. You may be able to substitute the cheese with something else.
Ingredients:
- 18 fresh corn tortillas
- 1 lb. ground beef, chicken, or meat replacement crumbles
- 2 cups vegetable broth (if using meat substitute)
- 2 cups grated sharp cheddar, or cheese substitute
- 2 cups enchilada sauce
- 1 cup sliced black olives
- 1 cup sautéed mushrooms
- 1/2 cup fire-roasted peppers, in adobo sauce
- 1/2 cup minced onion
- 3 cloves garlic, crushed, or minced
- 3 chipotle peppers, seeded and sliced
- 2 tbs. cooking oil
Heat vegetable broth to a simmer. Add the meat substitute; remove from heat; and cover.
Heat vegetable oil over medium heat until it shimmers. Add onion. Cook for three minutes, or until translucent. Add the mushrooms, and garlic. Cook another three minutes. Add the enchilada sauce, and peppers in adobo sauce. Stir to combine. Cook for another five minutes, bringing the mixture to a simmer. Add the ground meat, or meat substitute. Simmer for ten minutes to reduce to a rich sauce mixture.
Place 2 tbs. cooking oil on the bottom of a casserole dish, or laof pan. Spred 3 tbs. of just the sauce over the bottom of the pan. Lay down enough tortillas to cover. Evenly spread sauce/meat mixture on top of the tortillas, followed by black olives, chipotle peppers, and shredded cheese. Top with another layer of tortillas and build as with the first layer. Top with final layer of tortillas, and cover with remaining sauce and cheese. Cover pan tightly with foil. Place in 350' F. oven. Bake for 30 minutes. Remove foil, and place under the broiler for 2 minutes, to brown the top a little. Serve with horchata, or your favorite beverage. Might I suggest flan for desert?
Tip: grilled corn on the cob, seasoned with Tex/Mes seasonings is a great side for the meal.
Enjoy.
Seeeeya; Chief Longwind of the North
They are similar, but very different taste in the end product. 
