Preheat oven to 375 degrees Fahrenheit
In a blender, blend tofu, vegan egg replacer, soy milk, nutritional yeast, and all spices, until smooth. Mixture should be the consistency of very thick pancake batter.
Add oil to skill over medium-high heat. Once oil begins to ripple, sautee onions until fragrant. Add vegan sausage, mushrooms, pepper and kale, and cover. Reduce heat to medium-low, cook until kale is just wilted.
Pour blended frittata filling into large mixing bowl. Gently fold in 1/2 cup of shredded cheese and sauteed vegetables until well combined.
Spray a skillet or baking dish with cooking oil until evenly coated. Line bottom of pan with potato slices, leaving no gaps in beetween.
Pour filling onto sliced potatoes, using a spoon or spatula to spread evenly. Sprinkle with remaining cheese and bake for approx. 45 mins. until outer layer is golden brown around the edges and filling is firm to the touch.
Allow to cool for around 15-20 mins. Enjoy!