Preheat oven to 400F. Bring a pot of water to boil and while you're waiting, in a large saucepan add beef (or meatless substitute) along with 2 tbsp olive oil, 1 tbsp Italian seasoning, 1 tsp salt and 1 tbsp chili powder. Cook until meat is well done.
Once water is boiling, dice the potatoes and then add then into the water (I left the skin on mine). Cook until very soft. While potatoes are cooking add in cream of mushroom soup to the cooked meat along with can of corn, frozen mixed veggies & yellow onion. Cook for 5 minutes.
Once potatoes are done, drain water, return to pot and add in 1 tsp salt, 1 tbsp Italian seasoning, 1/2 tbsp garlic powder, 2 tbsp vegan butter & 1/4 cup oat milk, mash together making sure everything is well incorporated.
Add meat mixture to a oven safe cooking dish, top with mashed potatoes and bake for 30 minutes. Add vegan cheese on top the last 5 minutes (optional).