- Preheat the broiler.
- Toast the bread in a toaster on a medium setting—you don’t want it to get too toasted. Lightly butter the toast. Spread out half of the avocado slices on each of two slices of toast. Place both on a baking sheet.
- Sprinkle salt and pepper over the avocado. Drizzle or dollop cheese sauce on top. Place the baking sheet under the broiler for about 2 minutes, until the cheese is lightly browned.
- Remove from the oven and top with your desired add-ins (if using). Spread mayonnaise on the remaining slices of toast and place them on top of the sandwiches. Serve immediately.