Preheat the oven to 350. Lightly spray 6 muffin tins with non-stick cooking spray.
Add cilantro leaves to the bottom of each muffin cup, along with a pinch of salt and pepper. Crack an egg into each muffin cup. Top with cilantro and salt and pepper.
Bake in the preheated oven for 15-20 minutes, or until the yoke has cooked through.
Meanwhile, combine the mashed avocado with lemon or lime juice, leftover chopped cilantro, salt and pepper, all to taste.
Assemble the sandwiches once the baked eggs are cooked. I layered mine like this - English muffin - avocado/guac - baked egg - salsa - slice cheese - English muffin.) Then place in the oven on a baking sheet for about 10 minutes, or until cheese has melted.
Serve Avocado-Egg Breakfast Sandwich with side of fresh fruit.