Preheat oven to 400°F. Grease a large 13 x 9-inch casserole dish with olive oil.
Wash and prepare all the other ingredients. Doing so will make the final preparation and assembly quicker.
Wash and grate 4 large potatoes (skin optional). Soak the grated potatoes in a large bowl of cold water for 5-10 minutes. Strain, squeeze out excess water and transfer to a clean tea towel to soak up any extra moisture.
In a large non-stick pan, on medium heat, add 2 tablespoons of olive oil, onions, shredded potatoes and cook until soft and some of the edges get crispy (about 10 minutes). Season with sea salt, garlic powder and pepper to taste. Transfer to 13 x 9 casserole dish.
In the same large pan, add another tablespoon of oil over medium heat. Crumble up the breakfast sausage in the pan and cook until cooked through about 7-10 minutes. Transfer cooked sausage to a large bowl.
To the same large pan, add a little extra olive oil if necessary. Add the garlic, mushrooms and peppers and cook for 7-10 minutes. Toss in the greens cook until wilted. Transfer everything to the same large bowl with the sausage.
In a high-speed blender (or food processor), combine the tofu, nutritional yeast, flour, turmeric, sea salt, and blend until nice and smooth.
Pour the tofu mixture in the large bowl with all the other cooked ingredients and combine. Pour mixture overtop the potato layer in the casserole dish. Top with the shredded cheese and chopped green onions.
Bake in preheated oven for 35-45 minutes until edges are golden and the top feels set. Let cool for 10-15 minutes before serving. Enjoy!