Cut the avocados in half, remove the pit, and scoop the flesh into a bowl. Mash the avocado with a fork and mix in lemon juice, salt, and pepper to taste.

Heat olive oil in a skillet over medium heat. Crack the eggs into the skillet and cook to your desired doneness (sunny-side up, over-easy, etc.). Season with salt and pepper.

While the eggs are cooking, toast the bread slices until golden brown.

Spread the mashed avocado on each slice of toasted bread. Top with a cooked egg and any optional toppings like cheese, spinach, or tomato. Close the sandwich with another slice of bread.