1. Preheat the oven to 375 degrees. Slice the zucchini in half, longways. Scoop out the insides. Place on a cutting board and finely chop.
2. Combine zucchini with bell peppers and white button mushrooms. In a medium saucepan heat butter. Once melted, add zucchini, bell peppers, and mushrooms. Cook until soft and season as desired.
3. Remove from heat and place inside the zucchini. Top with tomato sauce and vegan shredded cheese.
4. Line a baking dish with foil. Place zucchini in the dish and bake for 45 minutes.
5. Once done, top with fresh parsley and scallions. Serve immediately.
A baking dish works best because the high sides stop the zucchini from collapsing but a baking sheet will still work as well.