1. Preheat the oven broiler.
2. Lay the toasted bread out on a baking sheet.
3. Top each slice of bread with 1/4 of the avocado, mushrooms, almonds, and tomato slices.
4. Top each with a slice of Swiss cheese.
5. Broil the open-face sandwiches until the cheese melts and begins to bubble, about 2 minutes. Serve the sandwiches warm.