Preheat the oven to 350°F (175°C). Line a half sheet pan (18 inches by 13 inches (45×33 cm) baking dish with parchment paper and lightly grease with olive oil.
 In a skillet over medium heat, heat the olive oil. Add chopped mushrooms and a pinch of salt and pepper. Sauté for 8–10 minutes, stirring occasionally, until the mushrooms release their moisture and the pan becomes dry.
 Add the bell pepper, onion, and baby spinach. Cook until the spinach is wilted and the vegetables are softened, about 2–3 minutes. Remove from heat and let cool slightly.

In a blender or using an immersion blender, combine silken tofu, nutritional yeast, chickpea flour, cornstarch, turmeric, garlic powder, salt, black pepper, vegan milk, and baking powder. Blend until smooth and creamy.

Add sautéed vegetables to the tofu mixture and stir gently to combine. Pour onto prepared baking dish and spread in an even layer.
Bake for 35 to 40 minutes, or until the top is golden and firm to the touch.
Allow the baked omelet to rest for 5 to 10 minutes, then slice into 10 squares.

While the omelet bakes or cools, cook vegan sausage patties according to package instructions or until golden and cooked through.

To assemble each sandwich, layer in this order:

Bottom half of toasted English muffin

One vegan omelet square

One sausage patty

One slice of vegan cheddar

Top half of muffin

Let sandwiches cool completely before freezing.