Remove the pit from the avocado and discard. Scoop out the avocado into a bowl and mash it with a fork. Add a squeeze of fresh lemon juice. Season with salt and pepper to taste.
Toast the bread until it is golden brown.
Slather the avocado mixture over the bread.
Eat immediately.
Notes
To remove the pit from the avocado: Cut the avocado vertically. Twist to separate the halves. Tap the knife onto the pit and twist slightly. The pit should release easily at this point. Use a spoon to loosen the flesh from the peel and scoop into a bowl. If making for a crowd, a potato masher works great to get the avocado just right.