Spread 1 tablespoon of butter onto each piece of bread. Sprinkle with garlic powder.
Add 2 tomato slices onto each piece of bread. Top with mozzarella, leaving a small bit leftover for the top. Add the mushrooms, bell peppers, and sausage on top, and sprinkle with the remaining mozzarella.
Place in air fryer on Air Bake at 400°F for 10 minutes, until cheese is melty and toast is crispy.